Online survey scammers play the numbers game. Usually, they set their price pretty low for whatever they're promising. That way, they can get people signing up in droves. Their sign up/membership fee is a way for scammers to get your money and call it "validation."
Another method they use is creating false lessons. “We'll teach you how to make money taking surveys for only $34.95!” This “for only $” should be a giveaway that their site might not be on the up and up. So keep this in mind before you sign up for their “can't miss” online course.