We have permanently dropped the price of all our D20-era/OGL PDFs on DrivethruRPG, meaning there are some real bargains to be had. Even the biggest 256+ page books are a mere $5.99, and most titles are $3-4.99, with some even less than that!
You can see the full range of these titles at http://rpg.drivethrustuff.com/index.php?cPath=161_201
Now that's some kickass discounts!
Good thing this was permanent since my budget for this month is already spent...Would have hated if it was like "for 1 week"