> ## Documentation Index
> Fetch the complete documentation index at: https://docs.zeroclick.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Plans and pricing

> The four billing modes, plan meter prices with unitSize and includedUnits, and the whole-cent and six-decimal precision rules.

A plan defines how agents pay a seller. Each plan has a billing mode, a few plan-level money fields, and a set of **plan meter prices** that put a price on each [meter](/concepts/stores-services-meters). Together they determine what a 402 challenge costs and what an [allowance check](/concepts/usage-and-allowances) draws against.

## The four billing modes

| Mode                 | For the buyer                                                                                                            | For allowance checks                                                                                                                                                 |
| -------------------- | ------------------------------------------------------------------------------------------------------------------------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `payg`               | No purchase. Each call returns one priced 402 with the exact cost; pay and retry.                                        | Covered by the verified per-call payment, by included units in free mode (claimed agents with a verified email only), or by a prepaid balance the buyer still holds. |
| `credit`             | Prepay a balance of at least `minimumPurchaseUsd`, call until it runs out, top up any time.                              | Passes while `remainingCreditUsd` covers the declared usage at the plan's prices; otherwise denied `usage_exhausted`.                                                |
| `subscription`       | Purchase once at `basePriceUsd` for the period (month or year). Calls are allowed while the period runs.                 | Passes while the access period is current; a lapsed period is denied `plan_expired`. No usage balance is burned.                                                     |
| `subscription_usage` | A subscription whose purchase also grants `includedCreditUsd` of usage; usage beyond it is metered and charged per call. | Passes while the period is current and the included credit covers the declared usage; beyond it, per-call charges take over.                                         |

Plans carry an `interval` (`none`, `month`, or `year`) that sets the access period a purchase grants, and three money fields:

* `basePriceUsd`: what a subscription purchase charges; a whole-cent amount.
* `includedCreditUsd`: the usage credit a `subscription_usage` purchase grants; up to 6 decimals.
* `minimumPurchaseUsd`: the smallest credit purchase a buyer may make; whole cents, default \$0.01.

A purchase creates the buyer's [access grant](/concepts/agents-and-access), which later checks evaluate.

## Plan meter prices

A plan meter price attaches a price to one meter on one plan, with one price per meter per plan:

* `priceUsd`: the price, up to 6 decimal places.
* `unitSize`: how many units `priceUsd` buys (default 1). `priceUsd: "0.002"` with `unitSize: 1000` reads "\$0.002 per 1,000 units".
* `includedUnits`: free units per billing period before `priceUsd` applies (default 0).
* `defaultMaxQuantity`: an optional per-request ceiling, applied when a request declares neither a `quantity` nor a `maxQuantity` for the meter. Without a default, such an item is denied `meter_not_priced`.

Cost is quantity × `priceUsd` ÷ `unitSize`, rounded to six decimal places.

## A worked example

Acme prices the `output_tokens` meter of its `product-watch` service on a credit plan at \$0.002 per 1,000 tokens:

```json theme={null}
{
  "priceUsd": "0.002",
  "unitSize": 1000,
  "includedUnits": 0,
  "defaultMaxQuantity": 8192
}
```

A request that settles 4,523 output tokens costs 4,523 × $0.002 ÷ 1,000 = **$0.009046\*\*, deducted from the buyer's `remainingCreditUsd`. A request that declares no token count up front is gated and authorized at the 8,192-token default ceiling (at most \$0.016384). It settles at the actual count, and the remainder returns to the buyer. [Charge up to a maximum](/integrate/charge-up-to-a-maximum) covers ceiling billing from the seller's side.

If the price also carried `includedUnits: 100000`, the buyer's first 100,000 tokens each period would be free, and `priceUsd` would apply only beyond them.

## Two precision rules

1. **Money that settles on-chain is whole cents.** Buyer-chosen amounts (credit purchases and top-ups) must be whole-cent values of at least `minimumPurchaseUsd`, and `basePriceUsd` is whole cents. Because ZeroClick charges a pay-as-you-go rate call by call, a payg plan's `priceUsd` must itself be a whole-cent amount. The API rejects anything else with `422 payg_price_not_whole_cents` (see [errors](/resources/errors)).
2. **Catalog prices carry 6 decimals.** Prices on credit and subscription plans only burn prepaid allowance, so they keep full 6-decimal precision: sub-cent rates like `0.000250` are normal there.

`unitSize` is how pay-as-you-go expresses sub-cent rates within the whole-cent rule: the credit-plan rate above becomes `priceUsd: "2.00"` with `unitSize: 1000000` on payg. That is the same \$0.002 per 1,000 tokens, stated as a whole-cent price per million.

## Managing plans

ZeroClick sets up plans and prices with you during onboarding; you manage them afterward in the [dashboard](https://dashboard.zeroclick.io) or with the [REST API](/api-reference/introduction). Agents always read live prices from the storefront's `manifest.json`, so a price change takes effect on their next call.