Read the entire listing before you bid. Check out all the options, read all the Q & A's, double check the shipping costs. Sometimes the item may be cheaply priced, but the seller will just kill you on shipping. If shipping isn't even listed, I'd consider that a red flag.
   Most times a seller will hide a mention of a defect or missing parts somewhere in all the paragraphs. If it's a simple item and the auction page is huge, the seller may be hiding something. Make sure the picture is clear and the description is as well. A lot of sellers use stock photos off the Web or get the picture from another auction. Make sure the picture matches what the auction states it is for.
   You should always contact the seller before the auction ends if you have any questions about the item. If they do not return your emails then, they may not return them if a problem arises.