To make any money you do have to buy cheap and sell as high as the buyers will allow. So far I've sold all I've put on Craig's List, but I can't say I've made a real profit on all of them. And the three I've got on there now haven't sold. Some nibbles, but only from those who want something for nothing.
I may end up keeping more than I sell due to the buyers lack of interest in the old(er) machines. I could sell all the plastic junque machines I could make run, but sadly people just don't seem to have much interest in the real solid old machines.
And the economy has a lot to do with it. Central IL is a very economically depressed area. There isn't much employment that pays enough for people to have disposable income around here.
Joe