A thousand more users
For a normal app, a thousand more users costs almost nothing extra. AI apps are different: every question costs money.
WHY
Every token costs money
Because for every answer, the server has to run a giant model, working out each token. The longer the question and the more documents attached, the more it costs.
THE BILL
The bill goes to the product maker
Product makers pay the model company per million tokens. A large model can cost dozens of times, sometimes a hundred times, more than a small one.
FREE PLANS
Why free plans have limits
That's why free plans often limit messages per day, or only allow small models. Monthly plans are priced for the average user.
HEAVY USERS
Some people ask a thousand questions
Some people ask a few questions a day, others run thousands. Heavy users can make a product lose money, so many "unlimited" plans still come with fair-use rules.
TIP
A product maker's trick
A product maker's trick: give easy tasks to a small model, and only call a large model for hard ones. For questions that come up a lot, save the answer so you don't have to work it out again.
NEXT
Part 6: When AI products stumble
Cheap, fast and well designed, and it can still stumble badly. Part 6 tells three real stories.
This article is based on the video What each question costs from the Mark học AI channel. Watch the video (in Vietnamese) to see the animations.