Vindale Research is a GPT (get paid to) / survey/ product testing and evaluation site. Membership is FREE. Once you are a member you get compensated for evaluating different products and services. After signing up remember to fill out the member profile surveys so that you can be matched with the right earning opportunities.
The downside to this site is a lot of the offers require a credit card. I recommend using a pre-payed credit card when signing up for these offers just in case you forget to cancel the trial period. They do have some free offers that do not require a payment and those are the ones I choose to complete.
The upside to being a Vindale Research member is their referral program. They will pay you $5 for every person you refer. So if you can refer 2 people a week that's an extra $40 a month just for telling your friends and family to sign up.