I expect someone has already posted on online surveys. Don't be fooled by these. They do not pay you, or if they do, you have to spend money playing bingo or casino games.
I would think the testimonials on the websites purporting show winners are fictitious.
You don't get paid, you get points and have to have vouchers from companies that are of no interest to you. For example, on one site I have accrued 850 points. To get a £10.00 voucher I need 20,000! Considering I hardly ever qualify for the surveys this is a joke but I'm not laughing.
Don't be fooled by these sites. You won't make anything from them.