A good review site to start with is called No Kidding Coupons. When you join this site you will receive your products for cents on the dollar through Amazon, try the product and post a review. The product is yours to keep. The point of this site is to help companies get good reviews on their product to help their sales. The products range from supplements, beauty products, pet items and much more.
After you sign up and confirm your account you will receive your first 100 points, in which you purchase a coupon for %99 percent off anything in their Coupon Cart. While you are waiting for your first product look over the site and earn more points for more items.
I have already received two items through here myself and waiting on my third through the mail. I highly recommend checking them out and giving them a try, it is FREE to sign up. This is another place where Amazon Prime comes in handy so you can bypass any shipping costs.