I have one like this. Mine was quite dirty and the cabinet is in really terrible shape...a Martha Washinton type...electric. It was given to me, but he didn't think of it as anything but junk he had to clear out of his mother's house. ( I now have 4 of her machines...
Now, it's all cleaned up, a friend checked the wiring and found it to be sound, rewired the plug and it sews. I also have another White Rotary with the shiny finish. I'm very happy with it. If the cabinet is in good shape, it would be worth the $50, but it all depends how much you want to spend and what you'll do with it.