How do I collect a fixed payment deposit using Stripe?

Hello I have a Stripe account and once customers have booked a party with me I would like them to pay an immediate holding deposit of £50. I am not sure how I configure this on the form as it is a one-off price and not related to a product.

Can you advise?

Thanks 

Catherine

May we get the link to the form where you're working on? 

I think this will need to be set up as a product with the fixed amount you want to charge your customer, you could name this differently than products in your form and then it can be hidden as well, but we would need to get the form to provide the necessary CSS code to hide it. 

Additionally, you could  achieve this and include a fixed amount by setting up calculations to your form, this way you could display the products as basic fields and do the calculation, then include there the fixed amount. 

Here're some guides that will help you with calculations:

How-to-Perform-Form-Calculation-Using-a-Widget

How-to-Pass-a-Calculation-to-a-Payment-Field