Newegg offers the Synology DiskStation 2-Bay Diskless NAS Enclosure, model no. DS214se, for $139.99 with free shipping. (Amazon charges the same.) That's the lowest total price we could find by $15. Features include an 800Mhz processor, two SATA bays, 256GB RAM, and USB.
Amazon also offers the Synology DiskStation 2-Bay Diskless USB 3.0 NAS Enclosure, model no. DS215j, for $197.99 with free shipping. That's the best deal we could find for this model by $3, although most stores charge at least $206. It features a 800MHz dual-core processor, gigabit Ethernet, USB 3.0, and compatibility with JBOD and RAID 0 and 1.