From Gateway Software Productions:
Purchase Gateway enables you to perform invisible e-commerce right from your application. Purchase Gateway comes with an ActiveX control which you embed in your trial version. When the user wishes to buy, the control can collect all the necessary information then encrypt and transmit the information to a secure server; perform the transaction on the credit card for you; keep a running total of all your sales and send you payments monthly; or perform an "Extended Validation" which guarantees that the card is in good standing, then transmit the information to you via an encrypted e-mail. You can then use your existing merchant account to process the transaction, eliminating the high transaction fees that are associated with e-commerce merchant accounts. Lastly, it can send a message back to your application indicating the success of the transaction, and your existing demo locking mechanisms can be disabled, giving your user a fully enabled version of your software.