Your best bet is always going to be direct sales to other gamers.
I won't speak to price, but Half-Price books does buy gaming material.
Game Chest in the Valley View Mall probably does not, but they may know who does- they often traffic in older RPG material.
Generation X games in the midcities is also probably not going to buy them, but again, they may know who would be interested.
If you can't find a buyer, though, consider donation to charity. Lone Star Comics (many locations) has taken game supplies to give to the troops. You can also donate such things to the USO, Veteran's Hospitals, Boys & Girls Clubs, and other charities...but you should always ask first before making the donation.