Synology DiskStation DS115j, 1-bay NAS. Tested and working.
Sold diskless with no power adapter. You'll need a 12V 2A power adapter, about $12 to $15 on Amazon. Check the label on the back to confirm the rating before you buy one.
Specs: Marvell Armada 370 800 MHz processor, 256 MB RAM, 1 gigabit Ethernet, 2 USB 2.0 ports. Takes one 3.5" or 2.5" SATA drive.
Software: it runs DSM 6.2, the last version Synology released for this model. It won't take DSM 7, and Synology has stopped sending security updates. It's best for basic file storage, backups or media on a home network, not for anything exposed to the internet.
No drive is included. DSM lives on the drive, so it will set up fresh when you add yours. Ships within [1 to 2] business days. Feel free to ask any questions.