What this article covers (and who it’s for)
If you run an agency or an outbound team and your software costs feel like a bottleneck, this is for you. In a few minutes you’ll learn:
- How per‑seat vs. flat‑fee pricing really behaves as you scale
- Hidden costs most teams miss when they choose per‑seat
- A price comparison using real vendor pricing
- A simple TCO (Total Cost of Ownership) worksheet you can run in a spreadsheet
- When flat‑fee with unlimited accounts (like Instantly) wins and why
Per‑Seat vs. Flat‑Fee: Quick definitions
Per‑seat pricing = you pay per user. As your team or the number of connected inboxes grows, your bill grows at the same pace (plus add‑ons). Popular platforms using per‑seat include Mailshake and lemlist. Mailshake’s Email Outreach plan is $49/user/month and includes 2 email addresses per account; its Sales Engagement plan is $99/user/month and includes 10 email addresses per account. Billing is based on how many users you purchase.
Lemlist charges per user too: Email Pro is $69/user/month and includes 3 sending emails per user; Multichannel Expert is $99/user/month with 5 sending emails per user. You can buy additional sending emails for $9/month each per user.
(Another well‑known per‑seat example is Apollo, which lists $79 per user/month billed annually for its core plan.)
Flat‑fee pricing = you pay one price for the product, not per user. Instantly’s Outreach plans are flat and include unlimited email accounts (you rotate across them for scale and deliverability). The Growth plan is $37/month with 5,000 emails/month; the Hypergrowth plan is $97/month with 100,000 emails/month; Light Speed is $358/month with 500,000 emails/month. If you need more, there’s Enterprise.
Key takeaway: Per‑seat scales costs with people and inboxes. Flat‑fee scales outreach without scaling price.
Why per‑seat quietly inflates your costs
Per‑seat looks predictable on day one but as outreach scales, you’ll typically face:
- Linear seat creep: More users or more mailboxes = more seats (or add‑ons). That’s built into Mailshake/Lemlist pricing.
- Feature tiering: Want higher send volume per account, multichannel, or CRM features? You often jump to a higher per‑seat tier, upgrading everyone.
- Operational friction: Teams ration seats or share logins (bad for security/analytics), or spend time shuffling inbox allocations across users.
Bottom line: You pay more as you get better at outbound. At Instantly, we think that’s backwards and it’s one of the main reasons we built Instantly while running our own lead generation agency.
The flat‑fee advantage for agencies
Flat‑fee with unlimited sending accounts removes the seat tax. In Instantly:
- You connect as many inboxes as you want, rotate across them automatically, and scale send volume safely
- Plan‑level monthly send caps keep pricing predictable (5k, 100k, 500k+), and you upgrade only when total volume truly grows
- Setup is fast (buy sending domains in‑app with SPF/DKIM/DMARC and warmup handled), so you’re not burning hours on infra
Think of Instantly like an autopilot for outbound: you set destination and rules, Instantly rotates senders, warms domains, and maintains sending health so your team spends time on converting replies, not operations.
Price comparison: cost to send X emails/month
Assumptions we've used: 22 business days/month, 30 cold emails/day per inbox, so 660 emails/month per inbox.
Vendor pricing (checked Aug 27, 2025):
- Instantly Outreach: Growth $37 (5k emails/mo), Hypergrowth $97 (100k emails/mo), Light Speed $358 (500k emails/mo). Unlimited email accounts on all plans.
- Lemlist: Email Pro $69/user/mo, 3 sending emails included, $9/month per extra sending email. (We model cost with Email Pro to keep apples‑to‑apples on email - multichannel plan is $99 with 5 included.)
- Mailshake: Email Outreach $49/user/mo with 2 email addresses per account; Sales Engagement $99/user/mo with 10 email addresses per account, billing is per user. (We choose the cheaper mix per volume.)
How we compute inboxes needed: Inboxes = CEILING(Target monthly emails ÷ 660).
Example: 5,000 emails/mo → 5,000 ÷ 660 = 7.58 → 8 inboxes.
Cost table (USD, monthly)
| Monthly emails | Inboxes needed | Instantly (plan) | Instantly cost | Lemlist (Email Pro + $9/inbox > 3) | Mailshake (min cost mix) |
|---|---|---|---|---|---|
| 1,000 | 2 | Growth | $37 | $69 | $49 |
| 5,000 | 8 | Growth | $37 | $114 | $99 |
| 10,000 | 16 | Hypergrowth | $97 | $186 | $198 |
| 20,000 | 31 | Hypergrowth | $97 | $321 | $346 |
| 50,000 | 76 | Hypergrowth | $97 | $726 | $792 |
| 100,000 | 152 | Hypergrowth | $97 | $1,410 | $1,534 |
Daily sending aligns with current best practices for cold email.
What jumps out:
- At 20k emails/mo, Instantly is 3.3–3.6× cheaper than Lemlist/Mailshake.
- At 50k emails/mo, Instantly is 7.5–8.2× cheaper.
- At 100k emails/mo, Instantly is 14.5–15.8× cheaper.
The reason is simple: per‑seat cost scales with every extra inbox; with Instantly, inboxes are unlimited and your plan price is tied to total monthly sends—not headcount or sender count.
Cost per 1,000 emails (50k example): Instantly $1.94 vs. Lemlist $14.52 vs. Mailshake $15.84. That margin compounds into real agency profit.
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Beyond price: what actually makes scale possible
To send at volume without burning domains, three ingredients matter:
- Unlimited sending accounts + rotation. Connect many inboxes and rotate sends across them to keep per‑inbox volume low. (Instantly: unlimited accounts across all Outreach plans.)
- Infrastructure handled. Buying sending domains, auto‑configuring SPF/DKIM/DMARC, and warming accounts remove the heaviest lift. (Instantly does this in‑app and has done-for-you (DFY) email setup)
- Send‑cap smartness. Plan‑level monthly caps give predictable cost while your per‑inbox daily volume stays in the safe 30–50 range.
A simple TCO worksheet you can copy
TCO (Total Cost of Ownership) goes beyond your subscription fee:
- Licenses: Seats, add‑ons, required plan upgrades.
- Infra: Domains, auth (SPF/DKIM/DMARC), warmup tools.
- Integrations: CRM and middleware costs.
- People time: Onboarding, campaign ops, list hygiene, troubleshooting.
- Opportunity cost: Time spent juggling seats/add‑ons instead of booking meetings.
Quick example (illustrative): 10‑person agency sending ~20k emails/mo
- Per‑seat stack (mixed tools): $300–$400/mo in seats for email alone at this volume (see table), plus add‑ons and wasted time managing inbox allocations.
- Instantly Hypergrowth: $97/mo covers all sending accounts. You shift hours from seat wrangling to copy, targeting, and replies.
When should an agency choose flat‑fee?
Choose flat‑fee with unlimited accounts when you:
- Manage multiple clients or brands and need many inboxes.
- Plan to scale sends beyond a few thousand per month.
- Want predictable budgeting without per‑user surprises.
In other words: if growth is on your roadmap, don’t let seats set your ceiling.
Why agencies pick Instantly
- Unlimited email accounts across all Outreach plans → scale without per‑seat penalties
- Predictable plan caps (5k, 100k, 500k+) → budget clarity as you grow
- Deliverability‑first setup (domain purchase + DNS + warmup in‑app) → faster launch, fewer gotchas
- High‑volume safety (rotation, warmup, analytics) → keep inboxes healthy while you scale
The bottom line
If you believe growth should lower your unit costs, not raise them, flat‑fee with unlimited accounts is the economic model that matches your strategy. That’s why we designed Instantly’s Outreach plans to scale capacity and not price when you add inboxes.
Start your free Instantly trial and see how fast you can stand up a safe, scalable outbound engine without paying per seat. If you want to send more than 500,000 emails/mo, book a demo.
Frequently Asked Questions
Q: How many emails should I send per inbox per day?
A: For sustainable deliverability, keep it to 30–50/day per sending account. This is the assumption we used in the comparison (we chose 30/day to be conservative)
Q: Does Instantly really allow unlimited email accounts per plan?
A: Yes. All Outreach plans include unlimited email accounts (you upgrade only when your monthly send volume crosses a plan cap).
Q: If I only send ~1,000 emails/month, is per‑seat cheaper?
A: Sometimes a single per‑seat license can be close - see the table (Mailshake $49 vs Instantly $37). But once you cross ~5k emails/month, flat‑fee usually wins by a wide margin.
Q: What if I also need a lead database?
A: Instantly offers SuperSearch (separate plan) with 450M+ B2B contacts and AI‑powered enrichment; you can bundle it as you grow.
Q: Do per‑seat tools cap monthly sends?
A: Many don’t cap monthly sends explicitly, but they limit how many sending addresses you can connect per user (e.g., Mailshake 2 or 10, Lemlist 3 or 5), which indirectly caps safe volume unless you buy more seats or add-ons.
