Newegg has the Astak Mentor and Foxit eSlick for sale right now at $99.99. There were actually 3 ereaders this morning, but I didn't hear about the sale until it was too late to get the Cybook Opus.
I wouldn't actually recommend that anyone get either of these ereaders if you want to use them as ereaders. They're using the same rather ordinary hardware; the only real difference is the software. The Mentor is running the stock Netronix firmware with Adobe DE support and the eSlick is running Foxit's own firmware. The last I heard, it was dreck.
I'm getting them for my collection, and if I'm lucky I might be able to install a good firmware on them (Pocketbook, hopefully).