"Bought the machine for 40 bucks and wondering if I should buy a new compressor or one that would fit
because most parts for this machine are obsolete*, repair it, or scrap it."
shot from the hip eh?
Sounds like you had an impulse buy moment, Seriously though, it depends on your intent, so are you really are going to keep it because you find it interesting, flip it, or dump it like a cheap date. ( Tsk! no commitment) a new compressor wholesales for around $200 for an R12 1/4HP & double that for basic labor.
Now go get 'em Tex.
*ALL of these machines are obsolete! but they are
so addicting! now if you excuse me I have to get back to staring into my VF56 Faygo machines Correct change only light...