# Billing

This site uses `🍥` inference credits as the billing unit. **Prices shown in the model marketplace are the final billing prices**, so no extra calculation is required.

## Billing Methods

This site supports two purchase methods:

- **Subscription purchase**: usually cheaper, valid for 30 days.
- **Usage-based purchase**: billed by actual usage, with no time limit.

Go to the [top-up/subscription page](https://www.gorouter.cc/purchase) to choose the purchase method that fits your needs.

## How Prices Are Calculated

Model billing has three parts: input, output, and cache. Each part has its own unit price.

### Group Multiplier

Different API key groups may have different multipliers. The group multiplier is based on the original model price, but the model marketplace already shows prices after multiplier adjustments. That displayed price is what you actually pay.

**Example**

Assume a model's original prices are:

- Input: `2.5🍥`
- Output: `15🍥`
- Cache: `0.25🍥`

When the group multiplier is `1.3`, the final billing prices are:

- Input: `3.25🍥` (2.5 × 1.3)
- Output: `19.5🍥` (15 × 1.3)
- Cache: `0.325🍥` (0.25 × 1.3)

These adjusted prices are the prices shown in the model marketplace and the final prices you pay. For specific model prices and group multipliers, see the [model marketplace](https://www.gorouter.cc/models).

## Purchase Options

### Subscription Purchase

Subscriptions are usually cheaper, but they are valid for 30 days.

When purchasing the same subscription repeatedly:

- It does not create multiple parallel copies of the same subscription.
- It effectively extends the duration.
- The later purchase takes effect after the previous subscription expires.

### Usage-Based Purchase

Usage-based purchases have no time limit and are billed by actual usage.

Go to the [top-up/subscription page](https://www.gorouter.cc/purchase) to complete the purchase.

## Related Links

- [Model Marketplace](https://www.gorouter.cc/models) - view prices for all models
- [Top-up/Subscription](https://www.gorouter.cc/purchase) - purchase inference credits
- [Invoices](https://docs.gorouter.cc/en/docs/gorouter/invoice.md) - learn how invoices are handled
- [Referral Rewards](https://docs.gorouter.cc/en/docs/gorouter/referral.md) - invite friends and earn rewards