>>1848473That is 120 dollars, not hundreds.
Here is all consumables including tires and tubes for a 90s MTB project. All branded stuff, might be able to even half the price for off-brand parts and not using premade cable sets. Hubs will probably need maintenance too, but that is hard to estimate. Rest of the parts I would get cheap/free from bike co-ops or peoples' parts bins.
And of course it takes time like any other hobby. I am luckily financially secure enough that I don't have to think about "what my time is worth" when I am off duty. You shouldn't do this shit if you don't enjoy it.