What AI writing tools actually cost over three years (the subscription math)
ChatGPT Plus, Grammarly, Cotypist, TypeTab — the honest three-year cost of every way to get writing help, and what those subscriptions actually buy you.
ChatGPT Plus costs $20 a month. Sounds harmless. That's $240 a year — $720 over the three years you'll probably keep it. Now do that math for every AI tool in your menu bar, and you'll find the "AI stack" quietly costs more than your laptop did.
Over three years, subscription AI writing tools cost $216–$720: ChatGPT Plus is $720 ($20/mo), Grammarly Pro is $432 on annual billing ($12/mo), Cotypist runs $216–$324 ($6–$9/mo). A one-time on-device license like TypeTab costs $49, once. The difference is who pays for the servers — and for everyday typing help, the servers aren't necessary anymore.
I build one of the cheap options, so weigh that. But I'll also defend the subscriptions where they genuinely earn their keep, because the honest answer isn't "subscriptions bad" — it's that most people are paying frontier-model prices for autocomplete-shaped problems.
The three-year math, laid out
Prices verified August 2026 — check current pricing before you buy anything, this stuff moves.
| Tool | Billing | Monthly equivalent | 3-year cost |
|---|---|---|---|
| ChatGPT Plus | $20/mo | $20 | $720 |
| Grammarly Pro | $12/mo annual ($144/yr), $30/mo month-to-month | $12–$30 | $432–$1,080 |
| Cotypist Plus | $6/mo | $6 | $216 |
| Cotypist Pro | $9/mo | $9 | $324 |
| TypeTab | $49 one-time | ~$1.36/mo over 3 years | $49 |
Three observations before anyone accuses me of stacking the deck:
First, the subscriptions in that table aren't scams — they're good products. ChatGPT Plus is $20/mo for frontier-model chat access, and that access is worth real money if you use it. Grammarly's grammar checking is polished. Cotypist is a well-made Mac autocomplete app — I wrote an honest TypeTab vs Cotypist comparison where it wins some rounds.
Second, the one-time license isn't magic — it's physics. A small model running on your Mac has no per-use server cost. Your machine is the server. Nothing metered, nothing to bill monthly.
Third, the $49 isn't the whole story either: you're trading frontier capability for local capability. More on that below, because it matters.
What subscriptions actually buy you
To be fair to the other side — subscriptions buy real things:
- Frontier model access. The big cloud models are still meaningfully better at hard reasoning, long-form generation, and research-shaped tasks than anything that fits on a laptop. If your work needs that, $20/mo is cheap.
- Infrastructure someone else runs. Sync, updates, model improvements, team features. You're renting a department.
- Constant improvement. Cloud tools get better every month without you doing anything. That counts for something.
If you use those capabilities daily, the subscription is a bargain. My problem is with the mismatch — and that's most of the market.
The mismatch: paying frontier prices for autocomplete problems
Here's the pattern I keep seeing. Someone signs up for ChatGPT Plus to "write faster." They use it for a month, love it, keep paying. Ask them in week twelve what they actually use it for: rewriting sentences, polishing emails, generating first drafts of boilerplate.
That's an autocomplete-shaped problem. It doesn't need a frontier model — it needs a small model that knows your phrasing, running where you type. Paying $720 over three years for that job is like commuting in a freight truck because it can also haul furniture.
For a lot of people, the same logic applies to Grammarly: if you use its full editor, team style guides, and plagiarism checking, great. If you're using it to fix typos and smooth sentences in emails, you're paying $432+ over three years for a job a local model does fine.
And here's the part that's awkward for the subscription side of the table: for the everyday typing slice of writing help, the local model isn't a compromise. It's better positioned — it's always there in every app, it works offline, it learns your actual vocabulary, and your drafts never leave your machine. I wrote about how TypeTab learns your writing style if you want the mechanism.
The graveyard problem
One more cost nobody prices in: tools die. The writing-tool market is a churn of relaunches, pivots, and shutdowns — the app you build your muscle memory on this year has a real chance of being sunset next year. When a subscription tool shuts down, you lose the tool and the workflow. When a one-time tool shuts down, you lose updates — but the app on your disk keeps running, and the model keeps running, because the model is on your disk.
I'll be honest about the limits of that claim: any small software vendor can vanish, including mine. Buy from vendors whose apps work without a constant connection to home, and the failure mode gets a lot softer.
When a subscription is the right answer
To keep myself honest:
- You need frontier capability. Research, long-form generation, hard analysis. $20/mo for that is fine. (Pair it with a local tool for the typing slice — that's my actual stack.)
- You write seasonally. If you type heavily two months a year, monthly-billing a tool and canceling beats a perpetual license.
- You want zero maintenance. Some people genuinely value never thinking about updates, models, or settings. That's a legitimate preference worth paying for.
For everyone else — people who type all day and want the everyday slice handled — the math favors local. TypeTab is $49 once, works on up to three Macs, needs no account, and the free trial gives you 100 word completions and 20 full-line completions before you decide anything.
FAQ
Is ChatGPT Plus worth it for everyday writing help? If you use frontier-model chat daily — research, long-form drafting, analysis — yes, $20/mo is reasonable. If your actual use is polishing sentences and speeding up everyday typing, you're paying $720 over three years for a job a small on-device model handles well. Many people run both: a subscription for hard tasks, a local tool for the typing slice.
How much does Grammarly cost per year? Grammarly Pro is $12/month on annual billing ($144/year) or $30/month on monthly billing — $432 to $1,080 over three years (verified August 2026; check current pricing). Worth it if you use the full editor and team features; expensive for basic typo-fixing.
Why is some AI software a one-time purchase and some a subscription? Subscriptions fund server costs: cloud models run on rented compute, billed per use, forever. One-time licenses work when the model runs on your machine — no per-use cost exists to bill. That's why on-device tools can charge once while cloud tools can't.
What happens to my one-time license if the vendor shuts down? The app on your disk keeps working — updates stop, but the model runs locally, so the core functionality doesn't depend on the vendor's servers. A subscription tool that shuts down takes the whole workflow with it. Prefer tools that work without a constant connection home.