Can You Earn Money Filling Out Surveys? -

I was just wondering if you can actually make from filling out surveys? A friend of mine is doing it and making some spare cash. Can anyone do it? I found one of these sites at http://link.mavnt.com/cpa.php?50079.5053... and I want to know if it is worth signing up|::::|I have earned some money from the source below. Its free to join and you can earn money or prizes or donate to charity your choice.