Use two desktop hard drives (aka the type you plug in, not a USB BUS powered drive). Use one to store and then keep a full clone on the second. Don't bother with solid state. This will be best mix of cost effectiveness and reliability. Don't get a RAID-5 array, or any Raid array at this point. They can be expensive, finicky and much more difficult to work with. You won't see the benefits. Keep files you're working on currently on your computer and buy a small portable drive as a mobile backup if you wish. Sort with Lightroom for photos or just spend the time to manually organize.