Back when I started back into Turbo I paid $300 for my TG+CD, w/cables and case. It included Soldier Blade (loose), Order Of The Griffon, Shockman, and 2 other games (I think). The CD unit was non-functional, but it was just a gear.
That was a couple years ago, but if I use it as a base price and then factor in a few other things I've purchased since then (these are prices I actually paid as a member here at PCE to other members);
TG+CD + games =$300CAD (local pick-up)
TE + 3 games (I think) = $100USD
SSC3.0 = $100USD + trade
So I paid about $500USD (exchange was fairly even back then) for everything and about 10 games. 10 good games mind you. There wasn't a Deep Blue in the lot.
I would say $600USD would be a decent price. GOT is only a $50 game if you're patient. The rest can be had for < $20 is you are not in a hurry with the exception of Ys I&II, and Ys III. I picked up the Ys games from GameTZ for $80.
$900+ is overpaying.
BTW, most of my trades are public around here so you can just check my post history. I just didn't bother.