I have not bought many cards the last two years or so-so, the stuff I have sent in to comc is mostly 2-10 years old. Lots of base cards, game used, parallels, etc. Most of my stuff books under $10. It all sells...how fast will depend on the price you are looking to set it at.
I sold a bunch of Yankees and Phillies stuff during the playoffs. Seems like several times each week, I get a player collector that buys 5 or more cards of the same player....someone bought about 30 Griffeys this week.
I can not say how pleased I am with how well the site works. I am selling stuff that I would just end up giving away.
My experience with A & G game used, are that people want them cheap! I turn down a lot of offer under $1.25 for these. I am not willing to get rid of them that cheap.