How do you manage sales of your phone apps on different platforms?

everyone
I am developing phone apps and would like to introduce them on AppWorld, and later on, sell them on another platforms too. Since I'm a new developer, I need your help. How do you guys organize the transactions among different platforms/markets, such as sales and payments? 
And also, to protect my products from piracy, I am thinking of using dynamic licence. If anybody use any good licensing service, please let me know!

1. I've used paypal - but they are expensive (~2.5% fee).
2. Another option, is to use google checkout - I've got some good feedback on it from friends that use it.

As for licensing, I would go with dynamic service http://www.licmax.com/ Good luck.

I always search good business apps. I found an app “Sales Ledger” in android market. There is no other app in android market to manage Client details, Invoices and receipts, calculate outstanding balance and send payment reminder to your client like this one.
https://play.google.com/store/apps/details?id=com.softcell.SalesLedger For productivity in sales I think the app “Follow up manager” in android market is pretty good.
It’s an all in one app which includes from follow up schedule to client report everything.
https://play.google.com/store/apps/details?id=com.softcell.Followupmanager