RAID is okay, but it’s usually a full-time solution (i.e. if you run your computer on a RAID, the drives are running as long as your PC does, so they get a lot of running hours). To be TRULY backed up, you need at least 2 copies of any given file (the source and the backup) and preferably a backup that is off-site (to eliminate fire/flood/theft/etc).
That said, a realistic/economic backup would involve at least one external hard drive that you only turn on when you’re running a backup and turn off immediately after. Once you have that external, the process by which you backup is entirely up to you -
- Just do a straight copy/paste from your internal drive to the external (simple but takes a long time, and can’t do a true system recovery since you’d be missing the MBR).
- Use Windows backup and tell it to backup to the external
- Get yourself some imaging software, such as Macrium Reflect (free), Acronis True Image Home, etc, which will allow you to do incremental backups and such.