I originally had three sites listed, but they have all gone downhill. The only one I still trust is Pinecone.
Taking surveys requires some time and effort in order to earn incentives such as checks, amazon gift cards, or prizes. Don't believe any site that claims members will make $1,000+ per month or sites that want you to pay them to access surveys. Below are sites that I have used and have found to be legitimate:
1. Pinecone Research
I have been taking surveys with this company for two years. They send you surveys, you take the survey, and you are paid $3 per survey. You can cash out via Paypal immediately. They also have a gift catalog now.
If you're not sure about a survey site's legitimacy, www.surveypolice.com lists reviews and complaints by users. Taking surveys won't replace your monthly income, but it can provide some extra cash along with opportunities to test products and influence products sold in stores.