Short answer PeerPlay's referral program pays $2 once the referred developer registers their own app, gets five separate testers with at least three active days each, and puts in three testing days themselves. Payouts are reviewed by hand at first, because an earlier bug had already left wallet ...
Source: [Dev.to](https://dev.to/vmzavas/how-i-built-a-referral-program-to-find-android-testers-1hkg)