Back in the early 2000's I bought a full season of Star Trek: The Next Generation on DVD for dirt cheap on ebay. I got the most home-job, BS fakery I have ever seen. Needless to say, it didn't work. Since then I have been as careful as I can be. It sucks but I am not surprised at that number.
I find usually when something is well under priced. There is a strong chance it is fake. Tough to be aware of that all the time when we all love a good deal!!