Hmmmm. I would assume Fox is more valuable so I would probably bump that up a little bit. Maybe 120$? As long as they're in good condition, I think those prices are respectable given the retailers no longer have them.
I wonder if the same will happen to MGS2 Raiden and Liquid. It's hard to predict how sought after these PAK will get. We have Raiden, Snake and Fox but on the other hand we have the PW lineup and Meryl that's still the same price.