This is my take on this:
(and I have been on ebay pretty much since the inception and I have 100% positive feedback and my feedback score is in the thousands -albeit bought 90% more than sold)
-avoid (and flag) sellers who are trying to make money from overcharging shipping fees. In addition to being a bad karma, it is a straight fraud (here is is this Cinelli bar for $0.99 with a $30 flat shipping charge.) You/one should know that these people are there to make money and don't care about the quality of what they sell. Anyone can do better than that and assume what you might get is crap.
-then is the gamble: sh*tty shots of something that you hope that it is what you hope it is. The odds beat Vegas gambling, but this is the territory we are talking about.
live and let live, but darn it, be smart about it..