Return a budget. For example,

{
    "id": "1759183",
    "sellerId": "321392",
    "campaignIds": [
        143962
    ],
    "budgetType": "Capped",
    "amount": 1000,
    "startDate": "2021-01-11",
    "endDate": "2021-01-12",
    "spend": null,
    "status": "Active"
}
        

A budget limits the spend of a seller for one or more campaigns.

There are three types of budget:
Uncapped budgets put no limit on the total amount of spend.
Capped budgets limit the total spend to a fixed amount.
Daily budgets limit daily spend to a fixed amount.

In addition, budgets can limit the spend to a specific range of dates using the start and end date attributes. Finally a budget must be active to be used.

Spend approximates the current spend against this budget. There may be a lag between when an ad is clicked and the time it accrues to the spend. Daily budgets show spend against the most recent day only.