Used power tools on Ebay

[pwgrasshopper]

Ebay usually has basic model Taig lathes and Sherline mills up for bid. I don't have a clue what to look for in the pictures or questions to ask sellers. I would hate to get a "bargain" price and then have to sink a bunch of money into it for new parts.

Could some folks with machining experience provide some advice on how to increase my chances of getting a quality used machine? I just can't justify the price of new equipment.

Thanks