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Budget free AI usage before scaling it

A unit-cost method for AI free tiers: count completed tasks, retries, tools, and support, then choose limits and explain them clearly.

Jared Castronova

The short version

  • A free tier can create variable model and tool costs. Measure your own workload before choosing its limits.
  • Count completed user tasks, including retries and failed attempts, rather than treating one request as one unit of value.
  • Finite trials, usage allowances, and paid overages are options to evaluate, not a mandatory three-tier recipe.
  • Define signup cohorts and paid outcomes before reporting conversion. Registered and paying account totals alone are not a conversion rate.

An AI product can offer free usage if the team understands what that usage costs and what it lets a prospective customer evaluate. Start with the completed task, the requests behind it, and the boundary that stops additional spending. Freemium’s viability depends on those economics, not on a universal rule that AI products must charge immediately.

The pricing decision needs a workload record. A short prompt, a long document analysis, and a task that retries several tool calls can have different costs even when the interface gives each a single “run” button.

For a founder preparing a pricing page, the first useful artifact is a cost sheet for a representative user task. It lets the product team choose an allowance and the marketing team explain it without implying unlimited use.

What does a completed task cost?

Follow one task through the system. Record the initial request, model calls, retrieval, tool use, retries, and final output. Include failed attempts when you’re calculating the cost of producing usable results. A task that never completes still consumes resources.

API pricing separates input, cached-input, and output token charges. Model, context length, and processing options can affect the applicable rate. Use the current rate for your chosen configuration rather than a generic “cost per generation” estimate.

Add other variable costs your workflow incurs, such as storage, retrieval, and paid tool calls. Keep a separate record of support and human review. Some costs are metered directly, while others need an allocation based on your own operations.

The AI purchasing test uses the same principle from the buyer’s side. The useful comparison includes the work required to make an output usable. A fast draft and a completed customer task are different measurement units.

How can you budget an allowance?

Choose an initial budget from observed workload and the amount you’re willing to spend on evaluation. Then test what happens when a user reaches the limit. The interface needs to tell them whether work stops, waits, switches modes, or becomes paid usage.

Here’s a constructed planning example, not a client result or a quoted vendor rate. Suppose 1,000 active free users each complete 20 tasks in a month. At an assumed model cost of $0.03 per completed task, model usage totals $600. Doubling completed tasks doubles that subtotal if the cost per task stays unchanged.

That calculation excludes support, storage, retrieval, and any tool fees not included in the assumption. It also assumes failed attempts were already counted in the completed-task cost. Change the inputs before using it in a real budget.

Inspect the range. Record typical tasks and expensive tasks separately. Averages can conceal a small group using long inputs or repeated retries. Decide whether the allowance should count tasks, credits, tokens, or another unit that your system can measure and your users can understand.

Tool use can add tokens and separate server-side tool charges. This is a reason to inspect the entire task. A visible answer may sit at the end of several billable operations.

Which pricing boundary fits the task?

A finite trial, a recurring allowance, and paid usage can each be reasonable choices. Pick a boundary that lets a prospective customer evaluate the core task while keeping the cost and failure behavior visible.

OptionWhat the user can evaluateWhat you must define
Finite trialA bounded number of complete tasksExpiry, limits, and what happens afterward
Recurring allowanceOccasional use over timeReset timing and eligible operations
Subscription with included usageRepeated use within a stated budgetIncluded usage and overage controls
Metered usageWorkload that varies by customerBillable unit, spending limits, and reporting

These are options, not a recipe requiring every product to offer all four. Check whether your chosen unit feels predictable during a real task. A credit balance is less useful when the user can’t see what causes it to fall.

A historical example illustrates the communication problem. In July 2025, Cursor clarified its included model-usage pool and optional extra usage, acknowledging that the original explanation had caused confusion. That is evidence about a particular pricing rollout, not a claim about its current plans or a guarantee that the same model will fit your product.

What should count as conversion?

Define the population and observation window before reporting a percentage. For example, choose a signup cohort, the qualifying paid event, and the period in which that event must occur. Track completed tasks and spend within that cohort so you can examine the relationship between evaluation and payment.

Don’t divide unrelated lifetime totals and call the answer a free-to-paid conversion rate. Dropbox’s 2018 filing reported registered and paying account totals. Those totals don’t establish a signup-cohort conversion rate or the cost of carrying each free user.

Avoid assuming that a synthetic buyer’s willingness-to-pay answer predicts a purchase. Use modeled scenarios to prepare questions, then distinguish them from observed usage, paid transactions, and direct customer evidence. Missing evidence should remain visible on the cost sheet.

What should the pricing page explain?

State the included unit, reset or expiry, and the behavior at the limit. If extra usage requires a separate choice, show that choice before it creates spending. Have the product owner verify the wording against the implemented controls.

Revisit the sheet when model rates, task behavior, or limits change. The bounded async-work method explains how to define stopping conditions for workflows that can otherwise keep consuming resources.

Measure one representative task and test its limit before promising a free allowance. If a pricing-page improvement or internal marketing workflow needs implementation, Custom AI Builds can cover a defined project. You can book a call to discuss that scope. Product pricing economics and willingness-to-pay validation remain your team’s decisions.

Written by

Jared Castronova

Founder of JAC Growth Marketing. 12 years in marketing, from startup to IPO.

More about Jared

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