When free is not enough, what is the least you can pay for something that actually works? The paid tiers side by side, the cheap API option explained in one paragraph, and a decision flow you can use for anyone.
In this lesson you will
→Compare the entry-level paid plans by price and what they add
→Understand the pay-per-use option without any code
→Use a decision flow to pick for yourself or someone else
This is the lesson for people who have hit a free limit and want to pay as little as possible to make it go away. There are three routes: a cheap subscription tier, a standard $20 plan, or paying per use through the API. Each is right for a different pattern of use.
Figure 1.Almost everything sits at $20. ChatGPT Go at $8 is the only mainstream tier below it, and for a light user who just needs more headroom it is often enough.
Which cheap option fits which pattern.
Your pattern
Cheapest option that works
Why
Hit free limits sometimes, mostly short tasks
ChatGPT Go, $8
More headroom without the full $20
Write or read long documents most days
Claude Pro, $20
Long-document strength is what you are paying for
Live in Gmail, Docs and Drive
Google AI Pro, $19.99
Integration plus extra storage in one fee
Research daily and need sources
Perplexity Pro, $20
Search-first with citations
Occasional bursts, long quiet stretches
Pay per use (API)
You pay nothing in a quiet month
The pay-per-use option, in one paragraph
The same models are sold to developers by the amount of text processed, priced per million tokens (a token is roughly three-quarters of a word). GPT-5.4 mini costs $0.75 per million tokens in and $4.50 out; Claude Haiku 4.5 is $1 in and $5 out; DeepSeek V4 Flash is $0.05 in and $0.16 out. A typical chat message costs a fraction of a cent. For someone who uses AI in bursts, this can be cheaper than any subscription, and there is a free playground on this site to feel it. For someone who chats every day, the $20 plan is usually cheaper and comes with an app. Subscription vs API does the arithmetic properly.
Try it
This ran on a model costing well under $1 per million tokens
Three free runs a day on the site key. Add your own key for unlimited runs.
Figure 2.Read left to right and stop at the first yes. If nothing fits, the decision engine asks a few more questions and ranks the plans for you.
Knowledge check
You use AI heavily for two weeks every quarter and barely at all in between. Which is likely cheapest over a year?
Lesson FAQ
▸What is the cheapest AI subscription?
Among mainstream tools, ChatGPT Go at $8 a month is the lowest paid tier at the time of writing. Most other paid plans (ChatGPT Plus, Claude Pro, Perplexity Pro, Cursor Pro) are $20, and Google AI Pro is $19.99.
▸Is the API cheaper than a subscription?
For occasional or bursty use, usually yes, because you pay only for what you process. For daily conversational use, a $20 plan is often cheaper and includes the app. Subscription vs API on this site does the arithmetic.
▸Should I pay for more than one AI tool?
Rarely. One paid plan matched to your main need, plus the free tiers of the others, covers almost everyone. Two paid plans make sense only if you have two distinct daily needs, like research and coding.
▸What if I pick the wrong plan?
All of these are monthly and cancellable. Try one for a month, notice what stopped you, and switch. The wrong plan for a month costs $8 to $20; the wrong plan for a year, unnoticed, is the real cost.
Finished reading?
Mark it done to track your progress through the course.
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