not related to gauging - but I did try to sell some items on Ebay recently, including one nice boxed working Sega Nomad with some games (but a lamer bid on it and I cancelled the order - will prob put it on here for trade/sell before I leave US).
anyway what I did notice on Ebay are the number of listings (attractive items, at least) in auction format on Ebay has really thinned. I dont see anything interesting, for example, when I search for PC Engine. It seems JP sellers no longer really hit ebay to try to sell their stuff.
and for US stuff I dont see much.. there was a nice fully complete Ys with the map etc, that went for quite a bit ($120+).
I didnt buy much recently, did pick up a Genesis TMNT CIB ($90) and a SMS convertor for Genesis CIB for $90 as well.