[Trivial Psychic]

The easiest way to spot knock offs is to know what you're looking at. As many people have stated, people now a days are very clever when it comes to producing knock offs, and the quality of many of them are beginning to fall right in line with the legitimate stuff. Many times though, you can tell a bootleg from an original copy by:

1. examining joints or articulation points (such as the Groot BAFs that were flooding Ebay some time back, they had screws in the joints as opposed to the double jointed elbows they should have had...)

2. differences in paint apps and colors (Such as the Black Cat Marvel Legends floating around now, which have different shades of blue in the hair, or again, that Groot, which had a lighter green wash over the body...)

3. accessories or scale of the item (there are a glutton of loose, bootleg Halo weapon sets on Ebay, which while the sculpts and paints are very good, are way too big for the figures they are being advertised for.)

Then there's serial #s, figure packaging and what not...Knowing and studying product pictures are the only way you will know for sure, and even then...there's a good chance you might guess wrong.

Knowing where you are buying from is helpful as well. If it comes from China, is loose, and from Ebay, chances are, it's fraudulent. But on the other end of the spectrum...if it looks good, fills in the holes of your collection, and saves you a few dollars on the way, who cares if it's fake or not. There are a lot of people here who have bought the China-pools (the army of multi colored Deadpools on Ebay) many of which were as good or better than the original figure, and are nearly indistinguishable to the naked eye. Many times, it will be only you that knows. It's all about what you value. It's your collection...enjoy it.