I am trying to prepopulate a price in a Stripe field.

It looks like you are using regular products in your Stripe payment field, for which prices were set up directly within the form, and the price of such products cannot be prepopulated or changed with URL parameters.

With URL parameters and prepopulation, we can only change the same values that a user can change as well. In other words, we can only possibly prepopulate the quantity of a certain product that is selected, or the amount in the "custom amount payment" field, as in the following demonstration form:

https://form.jotform.com/60635962856972?paypalDonation[price]=90

However, we cannot change the price of a product.

If you intend to provide your own custom price to the form from a database with URL parameters, you would need to use a different type of options in your payment tool - the "Custom Amount Payment / Donation" option:

https://www.jotform.com/help/49-Order-Form-Types

Alternatively, you can also perform your own price calculations directly within the form. This would be done by:

1. Using widgets such as Inventory widget to store your products if they are limited in numbers, or regular Drop Down/Radio Button/Check Box field if your products are unlimited in quantity.

2. Using form calculation fields to calculate the price:

https://www.jotform.com/help/259-How-to-perform-calculation-in-the-form

3. Finally, passing the calculated price to the Stripe payment tool for processing:

https://www.jotform.com/help/275-How-to-pass-a-calculation-to-a-payment-field

If you need further assistance, please let us know.