ONLY buy from dealers with a return policy, period. Even thou you can file a claim and automatically win it were you to buy from a vendor with a no-return policy, it's a hassle and not worth the effort compared to buying from a reputable dealer with a return policy. Ebay can be a great place to both buy and sell, but you have to be careful and buy only from people with perfect, or near perfect Feed Back (trust me, it's hard to keep it perfect, lemme tell ya) and one that offers a full refund policy and the most you'll risk is $5 or $6 in shipping.
Btw, Ebay is officially ending the 3, 7, and 10 day return policy and is forcing sellers to either offer no return or 14 days or great return policy. In some ways I'm okay with the change but it puts pressure on my bullion related sales since a dive in spot prices will most likely precipitate returns.