CECash had sites with over 6 months retention. They offer bonus access to other sites besides the joined one.
They also have a program where you get paid $20/3 free trial with no deductions, plus $5/monthly renewal (+50% of all dialer revenue), so that you can see in time how many recur and for how long, and see what sites are suitable for partnership (60%) with them while you still get paid per free trial signup (console free option available for the same payout).