I have no idea how I missed this. Well, yes I do, as there is a shitload of stuff on sale for the RPGNow GM's sale.
Spears of the Dawn (one of the best run Kickstarters I've supported, if not "the' best). Normally 10 bucks, it's $7.49 for the next 4 days. It an African themed fantasy RPG and very well done. I should be in a twice a month campaign as a player (go figure), so I'll let you know how it plays in real life, but it's on sale now.
Red Tide (campaign sourcebook and sandbox toolkit) can be had for $5.99 in PDF. I liked this enough to grab it in hardcover. Tables and setting. Good stuff.
Stars Without Number: Free Edition is still free. If you grab nothing else, grab this. It's probably the best OSR styled Sci-Fi ruleset out there. Remember, 25% off of free is still free ;)