The the scamming part has me wondering, because if you type GP100 in GB you come across several NIB GPs that you can Buy Now for much lower than $900; though they are still high in my opinion.
Nobody is forcing people to bid up a GP100 to $900+. People are getting auction fever. It happens, a LOT. Particularly the new buyers others have mentioned; the ones with little feedback. I presume that these are probably also "panic" buyers that are trying to scarf up whatever they can. Can't say I blame them necessarily, but they are doing it to themselves. If they are missing Buy it Now GPs for hundreds less, well, no offense but they are paying a couple hundred bucks of "stupid tax", as Dave Ramsey would say.
A fair price is the one that a seller is willing to sell for and a buyer is willing to pay. And it is determined on an individual basis. What you don't find fair, someone else will. And apparently, at least today, the average fair market price for many guns is quite a bit higher than some of us are willing to pay, myself included. But apparently, enough people are willing to pay these higher prices right now. So be it.
I also think it's a good bet that all the hysteria will eventually die down, and prices will come down as a result.