Buying an engine from ebay... GOOD OR BAD?

FWIW, I would only buy a used engine from anywhere if I could hear it run or a video that showed it run and the oil pressure etc.
I have been burned so many times to take someone's word for it and even then...
It didn't turn out to be more than a 50/50 chance.
If you don't hear it run and inspect it on the spot, then it's a core.
Period...