The 3rd edition print version of Basic Fantasy Role-Playing Game is out on Amazon, for under $5.
Also quite inexpensive on Amazon is the Field Guild, a monster book for the same game.
I've reviewed the game before, so has Tenkar. You can buy the entire range of books for this game for less than a single book of most of the other old-school clones. They're good stuff and I highly recommend it. A lot of applause needs to go out to Chris Gonnerman for putting together a great free product and then putting it out in print for a lower-than-PDF price.
Speaking of buying stuff on Amazon, check out this 30% any one book code. It's limited to $10, and one book sold directly by Amazon. I used it to pick up a copy of the Monster Manual, myself, and saved almost the full $10. The Basic Fantasy books are so cheap the coupon is hardly worth using, and that's a serious plus to the system above and beyond its quality.