No, never had problems on Ebay, but yes...I've been afraid like you before bidding.
THen I've learned to read all the possible information about the sellers, not only feedbacks (also if important), but also if they're My Poupette Recommended sellers, if they take position against fake items, if someone here has got a good opinion about that seller.
I do not prefer people selling only one kind of item: sometimes you can find a normal person who buys and sells like anyone else, but seriously. Then I carefully read the auction and look at the pictures. You have to understand if they're standard pictures, or taken from a real bag.Also I don't like if the description is standard.
If in that moment the seller has got 2-3-4 auctions of the same item.. then they can be fake items. Occations are...occasional.. preowned bags cannot be all the same. New bags also: if you can find one or two with a very good price, you're lucky. I see so many auctions of the new
Prada gauffrè. Well, if you go to the factory outlet of Prada (near my town) you'll never ever see ONE of them. So for me the ones I see on Ebay sold at 300 for example (250-260 dollars) are fake.
So, take your time, read carefully everything, ask for the opinions of experts here in the forum... as if you're in a village market, look for something original, also if preowned or not of the current collection (it's safer), and you'll probably have FUN!!