Not rude?? Would you go up to somebody and ask how much they spent on their watch? Their shoes? Their haircur?
The question is not 'how much do they cost' but 'what did you spend' which is rude.
OP said:
I am usually asked by people how much my bike costs or this and that costs. Recently a guy who wants to get into cycling more and graduate from his 70's era Kent road bike asks me how much as a complete system............Meaning bike, shorts, jersey, gloves, etc....
Sounds like the guy questioning the OP was wondering about getting into the sport and asking 'how much does it cost'. Don't think this is rude at all.