# Price

URL: /business/nouns/price · Id: `noun:price`

> A Price is the amount, currency, unit, and tiers of an Offer, embedded in it; zero is a Price.

A Price is the amount, currency, unit, and tiers of an [Offer](/business/nouns/offer), embedded in it; zero is a Price. A new Price is tested on a sibling Offer, never split within one.

## Properties
| Property | Type | Required | Description |
| --- | --- | --- | --- |
| `amount` | `money` | Yes | The amount and currency. One Offer has one amount per market: test a sibling Offer instead. Never randomized. |
| `unit` | `string` | Yes | What one unit is, such as a seat, a call, or a month. |
| `meter` | [Meter](/business/nouns/meter) | No | The Meter that counts usage, for usage pricing. |
| `from` | `string` | No | Lineage: the slot it compiles from, as `Hypothesis#<slot>@v<version>`. |
| `status` | `string` | Yes | One of `draft`, `fixed` or `retired`, set by its Offer. |

## Object
```json
{
  "$id": "https://api.sb/ledgerlark.com/prices/price_1",
  "$type": "Price",
  "amount": {
    "amount": 400,
    "currency": "USD"
  },
  "unit": "seat",
  "meter": "meter_1",
  "from": "Hypothesis#approach@v1",
  "status": "draft"
}
```

## Relationships
- <a id="rel-price-of"></a>A Price **is a price of** one [Offer](/business/nouns/offer): every [Offer](/business/nouns/offer) embeds one Price: amount, currency, unit and tiers; zero is a Price. `priceOf`, inverse [`pricedAt`](/business/nouns/offer#rel-priced-at).

## Lifecycle

| State | Meaning | Moves to |
| --- | --- | --- |
| `draft` (first) | Its Offer is a draft, so its amount, unit and tiers can still change. | `fixed` on [`Offer.published`](/business/events/Offer.published) when the Offer holds this Price |
| `fixed` | Its Offer is published, so it never changes; a new price is a new Offer. | `retired` on [`Offer.withdrawn`](/business/events/Offer.withdrawn) when the Offer holds this Price |
| `retired` | Its Offer is withdrawn; every Order and Subscription made at it keeps it. | None: it ends here. |

## Stripe
**Price** (`price`). The source of truth is db.sb, and Stripe holds a copy written from it.

| Property | Stripe field | Source of truth |
| --- | --- | --- |
| `amount` | `unit_amount` | db.sb |
| `meter` | `recurring.meter` | db.sb |

## Example
A currency-conversion API prices each conversion at `amount: 0.001` on the `conversion` [Meter](/business/nouns/meter), with the first 1,000 each month at zero. A sibling Offer tests `amount: 0.0008` in a second [Market](/business/nouns/market).