Are there legit PTCs left?

It seems that most of the PTCs that i have signed up with are gone.  I am scared of signing up with new ones even if they seem legit because i am becoming so paranoid with these PTCs.  They pay members when they're new to entice more members to join and of course to make more money.  After a few months, they start to disappear.  I have invested a lot of time and money on a lot of PTCs, i cannot afford to risk some more.  I wonder if there is any legit PTCs left?