Some of my favorite types of products are those whose raw material is other people's garbage. Indiana-based design educator Shelly Leer, who operates on the web as ModHomeEcTeacher, used to buy pre-cut wooden circles at Lowes to make ottomans. After they stopped selling them, she needed to find an alternate source.
(I know you shop mavens are scoffing, but for a DIY'er without a proper shop set-up, routing a circle can be a hassle. When you do it off a template using a bottom bearing bit, I hate the way you have to unclamp and re-clamp as you make your way around the circle, and set up level support for the router base outside the circle. And for those of us without overhead dust collection hoses, the floor-mounted shop vac hose provides another problem during circumnavigation.)
Leer found her solution—also stocked on Lowes' shelves, but with the attractive price of $0: The plywood spools used to hold electrical cable are discarded when the cable runs out. "Two perfectly cut round pieces of 5/8" plywood with a removable cardboard cylinder in the middle? Now we're talking," she writes in a tutorial on Design Sponge. "With a tiny bit of carpentry, I came up with a way to easily re-work these into frames for my upholstered ottomans. I would label this as a mid-level DIY project that you could complete in a weekend."
Once again, I encourage you design students, DIY'ers, Etsiers and craftspeople to look at local industries and retail outfits around you and find out what they regularly throw away. Free raw materials are better for your wallet and the environment and can save you some elbow grease.