What is the best $20 or less purchase you have made for your bicycle that made the biggest positive change in your life? Brake pads? Some magical grease or lube? Some little ergo farkle that made things fit better? The best biking socks ever?
Cmon folks, spill the beans.. share the low budget items that have really made your life better.
For me so far the cheap improvement item is a pair of $10 headlights from dinodirect.com that are actually useable for urban commuting and double as daytime white blinkers.