It's not just eBay...there are dishonest/unethical people all through the coin & currency marketplace...buyer BEWARE! If you're going to put a significant sum of money at risk, buy from a reputable, certified dealer that you know and trust...or directly from the US Mint/BEP.
I agree, many of them are terrible and aren't really TPGs. I have heard both sides of the PMG vs. PCGS argument and I don't know which is better (or less bad). I have heard some say PMG is less consistent but I have heard the same thing about PCGS. I imagine it's like PCGS vs. NGC.
I have seen some suggestion that grades, designations etc, can be variant on the name of the submitter - ie big auction houses verses Joe Schmow.
There is one auction house that I would trust with that big purchase of any bill and thats Heritage auctions, I've been dealing with them for quite awhile and and have bought all of my notes from them and never had a problem.I have only bought 2 notes from ebay, a gem unc 1928 $2 and a 1922 $20 gold cert.I had no problem but I just bought them to sell. Otherwise I would never buy a bill from ebay again mainly because there prices are to high and the 2 incidents I came across.And ever since I found this $20 gold cert that I sold to what I call a big time dealer it's left a knot in my stomach. I just really didn't expect it from a dealer that is selling bills that are in the thousands of dollars range and he even has one listed for almost 20 grand of couse its not in a TPG holder. Randy P.S. My $20 1906 is up to almost $600 with 2 days remaining.....Also when I sold him my note I was wondering what he wanted with such a grade when all of his where almost AU or better..Now I know
The one thing that stands out for me with Heritage auctions, or online sales, is they have huge images that are tell all tales sized. I get kind of spoiled with that and feel let down when you look at their competitors images, which are downright puny by comparison.