A web app I'm working on requires either an upfront payment or a small monthly subscription (<$10). Are there any standouts in the category?<p>Three primary considerations are reliability, affordability, and ease of integration. Excellent customer service is a bonus.
I use paypal. It's quick to setup and has Paypal IPN which is essentially a call back to your system to let it know that the funds have been received or an order has been made. You can also set up free trial periods and things like that. It's quite easy to use.