Ive done this like a year ago but I didn't pay anything, I just dug and found some survey sites. Surveys are offered to you through email or something and then you get to choose whether you want to do them or not. Frankly I think its a waste of time to do them but I did get a 1o dollar pay check once from one of the surveys, i think from survey spot.
I guess you always have to be cautious about these kind of things. But give it a shot, getting paid to do surveys isn't anything new so that in its self isn't a scam.