Whoa! Check out this incredible page I found over at Amazon. There are over 400 items that are effectively free since they give you the purchase price back for a future purchase. Some of these are trial size items, but some of them are big full size items. Use the link below to browse this full amazing list of items that are essentially free with the credit they give you towards a future purchase:
Note that this offer is for Amazon Prime members. However, you can get a FREE 30-Day Trial of Prime and take advantage of these offers during your trial.