I do ask that too, be cheaper just to buy another sewing machine. But it isnt repairing the machine as the labor cost!
Anyway thats my thought on the subject.
and if we could find a good manual to repair our own machines, that would be great. We do it for other things like car, stove, ref, fans, even computer! so why not find a manual for our machines that tell us how to? I am all for it too.