According to this WSJ story on TerraCycle:

The company has set up nearly 4,000 trash-collecting brigades across the country, mostly from schools, churches and other nonprofit groups. They are paid two cents per wrapper or pouch. TerraCycle covers the cost of collection, including shipping, by securing sponsorships from the various food manufacturers; typically $150,000 to $350,000 per year depending on how many brigades are sponsored. TerraCycle then sends the trash to its factories in Mexico to be refashioned into new products for retail.

So everytime you save a wrapper that was destined for the big old stinky landfill, TerraCycle and the company it is partnering with (for instance, Nabisco) donates from 1 to 5 cents (depending on the item) to the school or charity of your choosing.

According to the TerraCycle Web site, if you sign up for the Cookie Wrapper Brigade, for instance:

TerraCycle will mail out 4 prepaid collection bags to your address. Once a collection bag is filled with at least 50 wrappers please seal and drop off the filled bag at a UPS drop off location near you, the shipping is courtesy of Nabisco.

The Cookie Wrapper Brigade program will allow almost any individual and organization to save this non-recyclable packaging from taking up space in our nation’s landfills. To help motivate people, Nabisco will donate $0.02 to the charity or school of your choice for every cookie wrapper you collect. If you don't have a charity currently in mind, you may choose from a list of existing charities! There are no signup fees, no shipping charges and the program will never cost you a single penny!

Pretty cool Cheap Trick, don't you think? You get to be environmentally aware and you get to donate to a charity. A double feel-good whammy. Gotta love that.