I pick up every free/abandoned bike I come across. Those that don't appear worth saving always have had some component that was worth saving. Somtimes it takes 3 or 4 donor bikes to make 1 worthy bike, but in the end, I've had fun tinkering, increased my very novice skills as a bike mechanic, and built a bike that I can give to someone in the community in need. Occasionally I have to buy some new bits n' pieces - brake cable, tire, or tube, and I fund that by selling an occasional scavenged component on eBay. One old Raleigh I found had some Suntour barcons that I didn't need - that did real well on eBay and paid for shop supplies and those odds n' ends for the summer.