Simple payment portal?

Hi all,

I'm looking for a simple payment portal that will allow me to trigger a call on my server after payment. Any recommendations?

More detail: i want users to be able to buy 'codes' for actions on my (adult) site that can be used to unlock one-off actions (eg making a database search). The code should be emailed to the user and logged in a datai, then consumed when the user makes a request with that code.