I was looking at the stuff this site offers, holy crap, I didn't realize how many portals were selling the old AD&D manuals and stuff. They most certainly don't have everything, but there's enough there that old time PnP nerds need to take a look.

There's a sale on zombie-themed games that's been going on for a week. It ends in 6 hours. Some good buys include Outbreak Undead and All Flesh Must Be Eaten.
http://rpg.drivethrustuff.com/rpg_zombieweek.php

In light of Halloween coming up, there are also other indie game sales that have caught my interest, like Epoch and Ghostories. Check them out here:
http://rpg.drivethrustuff.com/rpg_saleguide.php?src=dgrc

Eclipse Phase is 50% off until 14th January. I don't often see EP on sale, so this is definitely something to take note of for sci-fi fans.

DTRPG has a Tabletop Day sale, and a few really good games are heavily discounted, including DCC RPG which is at 80% off. Check it out:
http://rpg.drivethrustuff.com/featured.php