I developed .NET application and planning to sell it on monthly/yearly subscription plans.
At first I found that Plimus has licensing system and everything else that I need, but when I finally decided to test it I found that they have many bugs in their system and it's imposible to use licensing system with recurring payments.
Can you recommend some other payment processor that can accept paypal but also direct credit cards
and that has all fancy options like discounts coupons, recurring payment and most important license key deliver system that can control customers license based on monthly payments.
PayPal have IPN which you can use to develop a system like that.
I haven't seen any off the shelf solution for it though.