When creating a goal, you can specify a revenue value to be associated with each conversion for that goal.
Revenue can be any value from 0 to 999999999999 with 3 decimal fields, and can be defined as any supported currency. To see the complete list of currencies available for conversion goals, see Conversion Goal Revenue Currencies. If the currency for the revenue value is different from the account currency, the revenue value will be converted to the account currency using the average daily foreign exchange rate.
When you choose to report revenue, you can either associate a fixed revenue for each conversion or report revenue for each conversion when it happens. In order to report variable revenue, you must make sure that you choose the "The revenue of this conversion action may vary" option for revenue setting. Also you must write some custom code to report variable revenue with UET. To learn more, see How to report variable revenue with UET.