Why is the payment in 2 steps?

The first payment will be the service fee of 5%of the overall cost of the app. upon completing the first step; the app transfer process will begin. Upon confirming that the app ownership has been transferred, the second step that is the actual app price will be paid to the seller. After completing the second payment, the buyer will be able to download the things necessary for the app such as the source code and graphic data.

Smartphone App Acquisition Marketplace
AppTrader
https://www.app-trader.net/