For me the price is a factor but sometimes it still pisses me off.
A while ago I won a cd on ebay and when it arrived, it was missing the back insert. I rechecked the item description to make sure that I didn't miss reading this info. When I looked at the description again, it didn't say anything about the back insert missing. I was a little upset but luckily the cd only cost me a couple of bucks. I emailed the seller and he said he would refund the cd (minus the initial shipping plus the shipping to return the cd). I was like, no way. Both shipping cost were double what I paid for the cd, so I just wrote it off as a learning expierence.
I did leave the guy a neutral feedback and of course he retaliated back with a neutral saying that he offered a refund.
Sometimes you just can't win