Battle Ball is US$7 on Amazon right now, and if you do the two-for-one Hasbro/Milton Bradley special and checkout codes, you get free shipping!
Also, if you go to a bricks and mortar ToysRUs, you can supposedly talk them into including Avalon Hill games (think Risk 2021 A.D. or RoboRally) by pointing to the Hasbro label on the box and holding your breath until you turn blue.
Thanks to Board Game Geeks for these tips!