In honor of Earth Day, check out TerraCycle, which uses old products like water bottles and food wrappers to create new items like cork boards, pencil cases, and trash cans. (And they're not overpriced just because they're recycled, either.)
Simply by reusing and recycling different waste streams, this company prevents thousands of tons of waste from going straight to landfills.
If you're looking to make an eco impact and earn a few dollars, you can join a free brigade, which is basically a team that tries to collect certain types of waste, from candy wrappers to Starbucks coffee bags. Each item is monetized, too, so, for example, you could earn two cents for every used drink pouch you turn in.
Obviously, this isn't a route to getting rich quick, but it is a great way to give something back on Earth Day (and throughout the year)...and you can justify the time expenditure with the small amount you earn.