Just found out recently, and I'm certain some of you might be interested -
Planescape: Torment, lauded by many to be one of the best D&D-based RPGs in existence for its fascinating characters and engrossing story, as well as being set in the rarely-used Planescape setting, is available for purchase
here for a measly 10 dollars.
Despite having a few eccentricities in how the game is played and paced, it's still a worthwhile investment if you at all like old-schoolish CRPGs or are entertained by a story of self-discovery and coming to terms with mistakes of the past.
Oh, and the music is darned good, too.