Pinecone Research
It is one of the most popular survey sites online. They pay you $3 for every completed survey by check. Sometimes you will receive a product that they give you to test and do further surveys on. I usually get one every 2 weeks. You will be notified by email when one is available. Pinecone is so popular that to join you will have to find an invite banner online. You can usually find one at AmyLynn's site .