This is going to sound so simple but it can save you a lot of hassle and lost money.
Before you bid, read the sellers feedback. 99.2% positive? What did the 0.8% have issue with and how recent were their negative responses posted?
Over the years as I've been perusing eBay I've learnt that some people just are out there to con people, and it is sad so you have to protect yourself.
Be sure that a product is genuine, ask to see actual photos of the item if the photo looks modified or taken from a catalogue, read all through feedback and see why other people might have complained about the service of the seller. If you don't like what you read, don't bid, find the item with someone else.
I know that this has saved me from could-be disasters over the years.