For Google Workspace and Microsoft 365 mailboxes, Icemail and InboxKit have the lowest list prices we found as of November 2026, at $2.50 per mailbox (Icemail's limited deal, or InboxKit on annual billing). If you want mailboxes inside your sequencer, Instantly and Smartlead sell them at $4.50 to $5 per mailbox. At hundreds of mailboxes, flat or bundled providers such as Inframail and Maildoso cost less, but they are a different kind of infrastructure.
Some tool links here are affiliate links (disclosure). Nerdy Joe is an affiliate of both Icemail and InboxKit, the two featured providers, and has affiliate links for Instantly, Smartlead and PlusVibe. We rank by use case, not by who pays us, and our Icemail review covers the featured pick in depth.
We did not test these providers hands-on. Every price comes from the vendor's own page as read on November 13, 2026, monthly billing unless noted, mailboxes only.
The best cold email inbox providers at a glance
| Provider | Best for | Price basis (as of November 2026) | Mailbox type |
|---|---|---|---|
| Icemail | Lowest list price for Google and Microsoft | $2.50 per mailbox (limited deal vs $3.50) | Google, Microsoft, Azure, IMAP/SMTP |
| InboxKit | Like-for-like Google and Microsoft with annual savings | $3 monthly, $2.50 annual | Google, Microsoft, Azure |
| Zapmail | Bundled Google plans | From $39 for 10 | Google Workspace |
| Cheapinboxes | Volume tiers on Google and Microsoft | $3.50 to $2.80 per inbox | Google, Microsoft (Azure) |
| Mailforge and Infraforge | Non-Google sending capacity | $3 or $4 per slot | Shared or dedicated servers |
| Maildoso | Very high mailbox counts | Bundles from $75 for 30 | Not stated on page |
| Inframail | Flat price at scale | $147 a month flat | Microsoft-backed |
| Mission Inbox | Monthly send caps with dedicated IPs | Lite $50 for 15 | Not stated on page |
| Smartlead SmartSenders | Smartlead users | $3.99 to $4.50 per mailbox | Google, Outlook, SMTP |
| Instantly DFY | Instantly users | $5 per account | |
| PlusVibe DFY | Managed setup | Tiers from $123 a month | Google, Microsoft, Azure |
What it costs: 10, 50 and 100 inboxes
Our arithmetic from list prices, monthly billing, mailboxes only, no domains or warmup add-ons.
| Provider | 10 inboxes | 50 inboxes | 100 inboxes | Notes |
|---|---|---|---|---|
| Icemail (Google/Microsoft) | $25 | $125 | $250 | $2.50 limited deal |
| InboxKit | $30 | $150 | $300 | $25, $125, $250 on annual billing |
| Zapmail | $39 | $164 | $299 | Growth $99 for 30 plus 20 at $3.25 |
| Cheapinboxes | $35 | $175 | $325 | $3.50 below 100, $3.25 from 100 |
| Mailforge | $30 | $150 | $300 | Shared IPs, minimum 10 slots |
| Infraforge | $40 | $200 | $400 | Quarterly billing; dedicated IP extra |
| Maildoso | $75 | $225 | $225 | Starter covers 30; Growth covers 300 |
| Inframail | $147 | $147 | $147 | Flat, up to 400 mailboxes |
| Mission Inbox | $50 (15) | Not published | Not published | Send caps per plan |
| Smartlead SmartSenders (Zapmail) | $45 | $225 | $450 | Plus $13 per domain per year |
| Instantly DFY | $50 | $250 | $500 | Plus $15 per domain per year; needs a paid plan |
| PlusVibe DFY | Tier based | Tier based | Tier based | Managed service |
Send caps, provider type (Google, Microsoft, SMTP or Azure), IP setup and warmup differ by row, so the cheapest line is not always the best value. To see how many inboxes your volume needs, use our guide on how many inboxes you need for cold email.
How we picked
We looked for providers that sell mailboxes for cold outreach, publish a price, and configure DNS for you. We grouped them by use case because a Google Workspace reseller, an SMTP pool and a managed service solve different problems.
We weighed published price, mailbox type, warmup, per-domain guidance, refund terms and stated limits. Where a vendor's own pages conflict, we say so.
1. Icemail: best low-cost Google and Microsoft mailboxes
Best for: founders and agencies adding Google or Microsoft mailboxes to an existing sequencer.
Icemail lists Google Workspace and Microsoft 365 mailboxes at $2.50 per mailbox per month as a limited deal against $3.50, with Azure at $29 or $30 per domain for up to 100 mailboxes and IMAP/SMTP at $18 or $49 per domain, depending on the page. It sets SPF, DKIM, DMARC and MX automatically, exports to sequencers such as Instantly, Smartlead and EmailBison, and offers an API, an MCP server and a white-label program.
What to weigh: Icemail's pages conflict on several prices, on refunds (case by case vs "all payments are final") and on warmup ("pre-warmed" on one page, a 14-day warmup timeline on others). Icemail holds mailbox credentials and Microsoft login codes, and 2FA cannot be turned off. Its terms ban reselling without written permission while a white-label program is offered.
Icemail recommends 15 cold emails per mailbox per day and 2 to 3 mailboxes per domain; our Icemail review explains the limits and the credential trade-off. Icemail says it is a Google partner, which we could not verify, and its Trustpilot profile showed 4.0 out of 5 from 16 reviews on November 13, 2026.
See Icemail's current mailbox prices, or read our Icemail pricing breakdown for every figure.
2. InboxKit: best for annual billing and published refund exceptions
Best for: teams that want Google, Microsoft or Azure mailboxes and are happy to prepay a year.
InboxKit charges $3 per mailbox per month monthly and $2.50 on annual billing, the same for Google Workspace and Microsoft 365, with "No plans, no base fee, no minimum." Azure is $30 per tenant for up to 100 mailboxes, pre-warmed mailboxes run $6 to $9, and warmup is a $3 per mailbox add-on.
The key difference from Icemail: InboxKit's acceptable use policy says its Google Workspace mailboxes are made available "under regional distribution arrangements for India" and encourages customers outside India to consider Microsoft 365 or Azure. If you are in the US or Europe and want Google mailboxes, confirm with InboxKit first. See InboxKit's pricing.
3. Zapmail: best bundled Google plans
Best for: Google Workspace buyers who prefer a plan to per-mailbox billing.
Zapmail sells Starter at $39 for 10 mailboxes, Growth at $99 for 30 and Pro at $299 for 100 (API included), with extra mailboxes at $3.00 to $3.50. Its page says "From $2.50 per inbox on annual plans," with pre-warmed mailboxes from $6. Mailboxes past one year move to "updated pricing," with no new rate given, and Microsoft is not shown on the pricing page.
4. Cheapinboxes: best volume tiers
Best for: buyers who want the per-inbox price to fall as they grow.
Cheapinboxes charges $3.50 per inbox from 1 to 99, $3.25 from 100 to 249, $3.00 from 250 to 999 and $2.80 from 1,000, the same for Google Workspace Business Starter and Microsoft. Its Azure bundle is $20 for the first month then $18 for up to 20 inboxes with a domain included.
At 1 to 99 inboxes, the $3.50 rate is $1 more per inbox than Icemail's limited-deal price. Cheapinboxes' FAQ says plans include "pre-warmed inboxes."
5. Mailforge and Infraforge: best non-Google sending capacity
Best for: senders who care about cost per send more than Google or Microsoft branding.
Both come from the Salesforge family. Mailforge charges $3 per mailbox slot (about $2.40 yearly) on a shared IP pool, with a 10-slot minimum that bills whether used or not, and recommends 30 emails per mailbox per day.
Infraforge charges $4 per slot billed quarterly on dedicated servers, with dedicated IPs at $99 per IP per month. Neither has a free trial, and .com domains cost $14 a year on both.
6. Maildoso: best for very high mailbox counts
Best for: operators running hundreds of mailboxes at low volume each.
Maildoso bundles 30 mailboxes for $75, 300 for $225 and 1,000 for $499 a month, and caps each mailbox at "up to 15 emails per day." The pricing page does not clearly state the mailbox provider type, and its guarantee wording conflicts between a 30-day money-back promise and a refund if deliverability drops below 80%.
7. Inframail: best flat price at scale
Best for: agencies that want one bill regardless of mailbox count.
Inframail charges $147 a month flat for up to 400 mailboxes (80,000 emails a month, one dedicated US IP) and $387 for up to 1,000 (300,000 emails, three IPs). It says inboxes run on "dedicated, Microsoft-backed infrastructure," includes 10 free .com domains, and includes warmup only on its $797 a month done-for-you plan.
8. Mission Inbox: best for capped monthly sending
Best for: teams that want a fixed send allowance and dedicated IPs.
Mission Inbox sells Lite at $50 (15 mailboxes, 5,000 sends a month) and Scale at $199 (30 mailboxes, 10,000 sends). Warmup emails count as sends. The provider type and per-mailbox price are not stated on its page.
9. Smartlead SmartSenders: best for Smartlead users
Best for: teams sending through Smartlead who want one bill.
Smartlead's marketplace sells Zapmail Standard mailboxes at $4.50 per mailbox plus $13 per domain per year, Mailreef SMTP at $3.99 plus $19 per domain, and InboxKit mailboxes at $4.50 plus $13 per domain. Whether an active Smartlead plan is required is not stated in the article. See Smartlead's plans.
10. Instantly DFY: best for Instantly users
Best for: Instantly customers who want Google accounts and warmup in one place.
Instantly sells done-for-you Google accounts at $5 per account per month, domains at $15 per year (.com and .org), up to 5 accounts per domain, with warmup on automatically. An active Instantly Outbound plan is required after the 14-day trial. Our Instantly review covers the sequencer, or see Instantly's accounts.
11. PlusVibe DFY: best managed setup
Best for: teams that want inboxes, warmup and sequences set up for them.
PlusVibe sells managed tiers: Google Workspace at $123 a month (3 inboxes), Microsoft 365 at $456 (5 inboxes), Azure at $789 (10+ inboxes with dedicated IPs) and a custom setup at $1,500 a month. It is a service, not a per-mailbox store. See PlusVibe's done-for-you tiers.
Icemail vs InboxKit for most buyers
Nerdy Joe is an affiliate of both, so here is the plain comparison by use case:
If Icemail fits, compare Icemail's mailbox types before buying. Our list of Icemail alternatives goes deeper on each option.
Policy and warmup: read this before buying anywhere
Every Google or Microsoft reseller works inside the same rules. Google's Workspace terms bar customers from reselling the service, and its acceptable use policy prohibits unsolicited mass email. Microsoft says "using Microsoft 365 to send bulk email isn't a supported use of the service."
No provider on this list makes these setups approved or risk-free. Plan for some mailboxes to be suspended and keep volumes modest.
On warmup, Google's sender guidelines recommend raising volume slowly to engaged recipients and do not mention warmup tools. Google has not published a position on warmup networks, so treat automated warmup as a practice Google neither endorses nor explicitly names. For the full setup, see our guide to cold email infrastructure and our ranking of the best cold email software.
Our pick
For most teams adding Google or Microsoft mailboxes to a sequencer they already use, start with Icemail or InboxKit and decide on billing cycle, region and refund terms. Our full Icemail review covers setup and limits, and you can start with Icemail on a few domains.
Rather not build the list yourself?
The inbox provider is the easy decision; the list, copy and daily sending routine are the work. Nerdy Joe is owned by Agency Growth Partners (AGP), and AGP builds verified lists and runs outbound for agencies. If you would rather hand that off, book a call with David.
Disclosure: My relationship with Instantly is that of an independent party. I do not hold any position, nor do I have the power to form binding agreements or act on behalf of Instantly. My earnings are derived from referral compensations provided by Instantly. The views I share are solely mine and should not be seen as official statements, promises, or representations of Instantly, or any related entities or personnel.
Sources
- Icemail pricing
- Icemail terms
- Icemail: Why Icemail
- Icemail: Google mailboxes
- Icemail: White label
- Icemail Help: Refund and cancellation
- Icemail Help: Sending limits
- Icemail Help: Why 2FA can't be removed
- Trustpilot: Icemail
- InboxKit pricing
- InboxKit warmup
- InboxKit acceptable use policy
- G2: InboxKit reviews
- Zapmail pricing
- Cheapinboxes
- Mailforge pricing
- Infraforge pricing
- Maildoso pricing
- Inframail
- Mission Inbox pricing
- Smartlead Help: SmartSenders pricing
- Smartlead Help: InboxKit mailboxes
- Instantly: Done-for-you Google email setup
- PlusVibe: Done-for-you email setup
- Google Workspace terms of service
- Google Workspace acceptable use policy
- Google: Email sender guidelines
- Microsoft: Outbound spam protection
Frequently asked questions
What is a cold email inbox provider?
It is a company that sells and sets up the mailboxes you send cold email from, usually Google Workspace, Microsoft 365 or SMTP mailboxes, with domains and DNS records configured. You then connect those mailboxes to a sequencer such as Instantly or Smartlead.
Should I use Google Workspace or Microsoft 365 for cold email?
Many teams use both so they can match prospects' providers and spread risk. Icemail and InboxKit sell both at the same per-mailbox price, so the choice does not change the cost much.
Are cheap cold email inboxes safe?
Price alone does not tell you. Google's Workspace terms bar reselling and its acceptable use policy prohibits unsolicited mass email, and Microsoft says bulk email is not a supported use of Microsoft 365, so no provider can promise mailboxes will never be suspended.
Do I need a separate provider if my sequencer sells mailboxes?
No. Instantly and Smartlead both sell mailboxes inside their apps, which is simpler but costs more per mailbox than Icemail or InboxKit at list price as of November 2026.
How many mailboxes should I put on one domain?
Most providers recommend 2 to 3. Icemail recommends 2 to 3, InboxKit says a maximum of 3, and Instantly's done-for-you setup allows up to 5 per domain.
Do inbox providers include warmup?
It varies. Instantly DFY includes warmup, InboxKit sells it as a $3 per mailbox add-on, and Icemail's standard mailboxes need about 14 days of warmup per its product pages; most sequencers include warmup in their plans.