I recommend you set up a separate email address for reviewing purposes. Many of the sites listed below will send deals to your email. Others, you go to and request things that you want. When you are approved for a product, you will receive an email with the Amazon link to the product and a code to order the product.
First thing you want to do before signing up to review is be a reviewer. Anything you have ever purchased on Amazon, go back and review it. You can go to your Order History from your account to see which products you have ordered. I also recommend that you have Amazon Prime. Otherwise, you’ll pay shipping. Prime pays for itself in credits if you choose the “No Rush” Shipping option. This option usually rewards you with $1 in credit for movies, E-Books, and music.
Here are the websites where you should signup. Most will ask for you Amazon profile. To find this, logon to Amazon. Then go to Amazon.com/profile. This is where your reviewing history is displayed. You’ll want to copy everything that is in the address bar at the top of your browser and paste it where they ask for your Amazon profile link.