Is this a good time to confess that I used to buy "just anything"... as in, "OMG! LOOK! A sewing machine! Gotta have it!!!"?
Now I look for potential in the cabinets, for good decals, and I make sure that the machine is complete. I figure if it's complete, it can be MADE to work, but more often than not, I can't fix the cosmetics of the machine...and I don't have the tools or desire to make parts to fix a cabinet. If I can't make it look good for display, then it needs a home where they either don't care about looks or can fix it themselves.