Several survey companies put money directly into your Paypal account each time you complete a survey. Pinecone Research pays $3 per survey. Each survey takes 15-20 minutes to complete.
Survey Spot is another site that pays cash -- up to $5 for each survey you complete. In addition, they have a drawing every three months where you can win $12,000.
Cash Crate pays just 50 cents for each survey, but they do offer one or two surveys each day, so if you visit the site regularly, that can add up.
Other sites reward you with points that you can redeem for cash after you reach a certain level.
My Survey pays points, even if you don't qualify to complete a survey you start and when you get 1000 points, you can get $10 or choose from a list of prizes.
LightSpeed Research works the same way.
Some sites including Inbox Dollars and MyPoints -- don't even make you answer questions -- just read emails. The rewards aren't as big as the survey sites, but you can usually win a gift card every couple of months if you check them out regularly.
Finally, there's Synovate -- a company that often sends out full-size samples for you to test.
Not all of these survey sites are accepting new members at this time, but if you keep checking back, you may catch them when there's an opening.