Hey Baris,
Yes, it’s not possible to create a Recurring Application Charge with a price of $0.00, unless you have a capped amount of greater than $0.00 as well. So, a request with price of $0.00 and capped_amount of $10.00 should complete successfully and accomplish what you want.
That being said, you have a couple options for affiliate shops. You can either make use of the test parameter, which you would set to true to ensure that no real charge is made. Or more simply, you could skip the charge creation flow entirely in your application logic for affiliate shops.
Both of the above options should allow you to accomplish what it is you’re trying to do and ultimately get your app listed on our Partner-friendly app list.
Edit: corrected for non-zero capped_amount value.