Good grief!!?? I brought a gas cap latch(not the original type) 2 or 3 years ago for my 73 750 and it might have been 30 bucks, from the dealer. You have to remember, how many can they sell? If you want the type that came with it, most are broken now. I have an original on a spare tank and when ever I open it I am very careful.
If you want it to look brand new, gotta pay to play. That said, you could get a dependable runner 400 or 500 dollars(not including bike price) without engine repairs, maybe. Gotta do the labor yourself, but thats part of the fun.
I think most people enjoy the wrenching , going to swap meets and lurking on Craig Lists. I do, cause maybe I'll find that RC30 for $1500, in mint condition.
Whoops, I ranted!
Steve