Cheapest way to put a hard drive on the internet.

I'm currently researching the cheapest off site backup system and it looks like leaving a hdd at a friends house is the best option. The only thing I am stuck on is how to access it remotely. I need a system on a chip that I can plug in to the hdd and Ethernet and that provides ssh access. My first thought was a raspberry pi with a sata to usb cable but since I will only be doing weekly backups it makes no sense to keep the drive spinning 24/7. I need some way to turn off the drive and then back on over the internet. From what I understand there are linux programs that can do it but only directly over sata because the command doesn't work on usb sata controllers.

What I need is a cheap linux SoC that has sata and ethernet. Does anyone have any ideas?