Version pricing amounts are optional, you could get someone started with your APP for free to get their feet wet, and offer different paid for versions with more functionality.

Commerce7 handles all the billing, retains a 20% fee, and pays out once per month to the partner.

Step 1 - Edit Version

Click the pencil next to Version 1 to set the pricing

Step 2 - Set Pricing

Enter amounts and click SAVE VERSION