Usage-based Pricing
A model where costs are paid in proportion to the actual resources consumed (e.g., number of tokens, API calls, compute time), allowing users to pay only for what they use without upfront fixed costs.
Detailed explanation
Why It Matters in Tool Selection
This model directly aligns AI model operational costs (inference costs) with business value. It is considered a standard choice for API-based AI services because it minimizes spending during early low-usage stages while enabling immediate scale-up during traffic spikes without the hassle of planning infrastructure expansion.
What to Look For
- Granularity of billing units (e.g., price per 1,000 tokens, price differences between input and output tokens)
- Alerting and automatic cutoff (quota management) features when usage thresholds are reached
- Whether volume discounts (tiered pricing) apply to lower the unit cost as usage increases
Examples
A typical example is when using the GPT-4o model, where the length of actual sent and received messages is measured based on a set unit price—such as $5 input and $15 output per 1 million tokens—and either billed monthly in arrears or deducted from pre-charged credits.