At the end of the survey(which takes agesss) they ask for your email address and then they give you a quote reference number, example been 74837, you wait for a confirmation email, then they ask for your paypal details, it takes 4 days for the payment to go in usually
if its like superdrug customer feedback survey, you fill it in then they give you a code at the end like TILL2131, write this onto the receipt and it gives you the ammount of that it says on receipt.
never put your card details to any 1 of them.
A lot of the paid survey sites will only pay you if you qualify for the survey after you do it. You also only get a very small amount of money from each survey (providing you DO qualify). Basically you have to do an awful lot of surveys, and qualify, to make any sort of money from them.
i think it works basically like this site works, u do the survey then they mail u a check or put it into ur paypal