PayPal Web Payments Pro integrated with WP, is there a plugin?

I’m currently setting up a site in WordPress for a UK taxi firm that generates journey quotes based on the fields selected in a form (pick-up, destination, time, date etc).

I’ve found a number of WordPress plugins that provide the facility to process ‘Direct Payments’ with PayPal, but all require actual products to be added to a store.

Does anyone know of a plugin that can provide me with the transaction facility ONLY (and 3D secure), and allows me to pull in dynamic prices based on the quote. (We have a Paypal Pro account)

Alternatively do I have to learn how do it from scratch (please let there be a plugin)?

Thanks!