We got Cache off Craigslist. She wasn't in the pet section though, she was in the barter section and the ad said, "Will trade pit bull for anything you have laying around your house." 4 bald tires that didn't fit any of our vehicles was all it took. They said they could not control her and as such, crated her 16 hours a day. They were feeding her kibbles 'n bits (which she was allergic to) and she was missing lots of fur and covered in open sores from the allergic reactions. They said the sores were from mange and their options were supposedly a $4,000 treatment or to euthanize her. So, they were treating the "mange" with no-name ACV on her kibbles 'n bits.
So, yeah, I'd take a dog off Craigslist if I felt it was the right thing to do.