I want to build a low power relatively cheep NAS that can hold at least two drives. I want to go the DIY route since I'm blind and would rather do everything from the command-line instead of relying on a third party GUI that may or may not be accessible. What would good hardware be for this? All the single board computers I've found appear to have either one or no SATA ports. I'd prefer a pre-built system that only requires hard drives but can build a computer from scratch if required.
I don't have the reputation to make this a comment, but I can find at least one 2.5 inch 3TB (and 4TB) HDD: https://www.amazon.com/Seagate-Laptop-2-5-Inch-Internal-ST3000LM016/dp/B01CHYIEXG . For your computer, I would recommend a motherboard with an embedded processor, such as the Celeron J-1900 which has a thermal design power of only 10 watts. You could save money on your power supply by getting a thin-mini ITX form-factor motherboard, in which an external power supply like ones seen in laptops plugs into the IO shield and is distributed through the motherboard. These usually have PCI-E slots into which you can plug a cheap RAID card.