Here are some of the best sites to join to get free products. There are alot more but not the best.
Bzzagent sign up complete some surveys. If you qualify for a campaign they will email you.
Influenster you get vox boxes which are random products.
Smiley360 you complete surveys to see if your a match.. they offer alot of missions.
Snugglebearden get to try new products from snuggle.
Houseparty apply to host party's they give out nice products
In home product testing they will send out emails to take surveys. I have only tested one product in a couple years of being with them.
McCormick consumer panel they will send you products to try
Mills advisory panel this is a panel for general mills you get to try new products.
Goodhousekeeping product testing panel test different products from Goodhousekeeping.
Tide development team I've signed up for this but haven't received anything yet
Pinchme Get free samples that you have to give feedback for. The samples go quick.
Johnson&Johnson neighborhood and friends Try out products for your opinion.
Crowdtap Complete tasks and get entries to win amazon gift cards they also have sample missions.
Momsmeet get free products to try, usually food.
Pink panelists facebook page you sign up there.
Amazon freebies or cheap deals
Get free or deeply discounted products for your reviews on amazon.
You have to have an amazon account and you will have to pay for shipping, unless you have amazon prime you can get 30 day free trial. Note: your going to want to add some reviews to your amazon profile especially if you have to get approved first.
Please if you review a product give your honest opinion.
Amzreviewtrader is by far the best site I have found so far they have a huge selection of products and a lot of free ones. They have thousands of products. You have to request and get approved.
Snagshout you start out with points and you can request one product and after you review you get more points.
Elite deal group they have new deals daily, products go fast.
Dollar deal reviews
All star review. They will send out emails when a product is available
Ilovetoreview This one is great they send you emails, but you have to be quick
Honest few they will email you deals
UberZon Club they send out deals daily
Home product testing
I found a really good list over at http://vonbeau.com/offer/get-free-and-discounted-products-to-review-on-amazon.htm and also has some tips about amazon.
As of today I have reviewed $2400 worth of stuff for under $30 about 137 items I got for barely nothing for exchange for my review.
Most of these I have gotten through Amz Review Trader and a few others.