I am looking to setup an online platform and will be testing the viability of the idea as a MVP on the WordPress platform, as it is what I am most familiar with.

The platform will be taking payments from users but there will not be any products. The payment amount will be pulled from a custom post field, so will be different each time.

How can I take payment without setting up products?
Should I do this with WooCommerce with a generic product and set the price and redirect to cart. Is there a way of using a payment gateway just for the transaction processing.