This is a tough question to answer without knowingwho the seller is. I managed to buy SEVEN wedding dresses on ebay in an effort to save money and ended up going to the store and buying one. It's been so frustrating!
first, I bought a "Lot of 5" dresses for $190 from a Charity auction on ebay. The five dresses were like a grab bag. You didn't know what you'd get til you got it. I hated ALL of them. I sold one on ebay for two dollars and the rest are at a consignment shop where I will get 40-50 dollars each if they sell. So I might break even on that, minus the shipping.
THEN, I bought a Maggie Sottero (Teresa) gown for $199.00. I REALLY wanted a M.S. gown. Because of my height and the detailing along the bottom, it was not as easy to alter as I had thought. After $250 in alterations, I still would have to wear two crinoline slips AND 4 inch heels to make it work! Since my wedding is in August, I really didn't want to be THAT bogged down in material AND be teetering on heels. (I'm still hanging on to this one for now)
After that, I bought another dress for $100. It was the first style that I really wanted from David's Bridal. It was almost perfect. I just had trouble with the length again. It was not as bd as the first one, but it would involve removing the lace bottom, cutting the satin, then replacing the lace, which my first seamstress said would be expensive. (Another one later told me it could be done for less, but I already ordered the NEXT dress). So I took this one to the consignment shop and will luckily get $225 if it sells.
So feeling completely desperate and defeated, I went to David's Bridal and ordered another dress for $599!!! It was good to talk to someone at the store who could help me figure out how/if the gown could be altered for me.
All of the sellers on ebay were great. And the dresses were exactly as described. The charity box was used dresses, the other two were new, with tags attached. None were overseas.
Just keep in mind that you lose the advantage of trying on the dress and determining if it looks and feels right and if it can be tailored to suit you. With all the money I spent on the wrong dress, I could have actually gotten the Maggie Sottero style from the bridal shop that would have REALLY suited me.