Thanks to Shawn Fumo, I've learned of a Webstore called DollarManga.com, which appears to be where ComicsOne is getting rid of their excess inventory.
True to its name, DollarManga.com has many of ComicsOne's older series for $1 each, not-so-old series for $3 each, and relatively recent items for 25%-50% off.
I ordered the following at $1 a piece: Joan vols 2 & 3; Goku: Midnight Eye vols. 1-3; Tomie vols. 1 & 2; Weed vols. 1-3; Crayon ShinChan vol. 1; and Sarai vol. 1.
The catch is that the shipping is somewhat expensive. For the twelve books above, the shipping was $19. That works out to a total of $31 for 12 volumes of manga, which is still a good deal.