Here's a link to the complete list of offers available: http://www.trainn.org/offlis.php
As you can see, there is every kind of offers available, and you will surely find one that you are interrested in.
Some of the most recommended offers are the following:
-Bingo offers: It gives you the possibility of cash-in out a lot if luck is on your side.
-Reunion.com: It cost about $14 for a 7-day trial!:
-CellaDerm: It cost about $9 for a 7-day trial!
-Stamps.com: It's another free Trial
-Blockbuster: It's a trial from a reputable company and cost less then $10!