D-LINK DSM-G600 is a NAS with

Internal 3.5” Hard Drive Support
Two USB 2.0 Ports For Additional Storage
Gigabit Ethernet Port
802.11g Wireless
Running powerpc-uclibc-linux (revB only)
Available under $130 (every once in a while $99)

I have setup a web page with some binaries and hacks to extend usability of this device. For example you can find there telnetd, dropbear ssh, [...]