Found these two while out looking for beginner's guides to HTML:
Version 3.5 Dungeon Master's Guide and Player's Handbook for a combined total of $12 in pretty decent condition.
I haven't played D&D since my sophomore year in high school but 3.5 kicks the sh*t out of 4.0 and the books are harder to come across, even in used bookstores so I figured why not?