Prices are what the market will bear. The price range starts at free and goes to over $500.
Not bragging: I got very lucky with this $20 NU50. It needs tires and tubes, clutch shoes, battery, drive belt, brake shoes, kick starter bearing, and the fork/handlebars are slightly tweaked. I "formed" them back to straight, but you know how "average" steel weakens with work hardening.