If there’s one very-important rule when it comes to schoolwork, it’s to save early and save often. I’d also add that you should save elsewhere, too. So here are five options for backing up your files.

First, some criteria.

1. Must cost under $100.

2. Storage space must be at least 500 gigabytes.

3. Must be relatively easy to set up and use.

And now, your options.

Western Digital 500GB My Book ($99.99)

Pros: It doesn’t look like an external hard drive, turns itself on and off with your computer to save electricity.

Cons: Included software is apparently slow, first generation of My Book drives had reliability issues (this is the second generation, though).

More info: You’ll likely see this drive in a fair amount of dorm rooms as it’s got a nice aesthetic and a relatively affordable price point. Setup should be easy and quick and the drive should work well on PCs or Macs.

The first generation of these drives had some issues with reliability. The case has no fan, so heat dissipation is important. Don’t set this up on top of a radiator or window sill, in other words.

Iomega 500GB Prestige ($94.99)

Pros: Runs cool and quiet, has an actual manual power switch for turning the drive on and off.

Cons: No software included (you’ll get a license to download EMC Retrospect, though).

More info: The Prestige’s aluminum case and Energy Star qualified power consumption will ensure that this drive runs cool and quiet. A dedicated on/off switch lets you shut off the device over holiday breaks and long weekends away.

Plus, Iomega has been doing the storage thing for a while so this drive has a good name behind it.

LaCie Ethernet Disk Mini Home Edition 500GB NAS Hard Drive ($99.99)

Pros: Network attached storage so you can hook this drive up to your network to read and write using multiple computers.

Cons: Somewhat troublesome with Macs, NAS setup not quite as simple as standard external hard drives.

More info: If your housing situation gives you control over your network and you want to be able to share files with your roommate(s) relatively easily, this is a great price for a 500GB network drive. First-timers or people looking for straightforward backup of one computer might be better off with a standard USB 2.0 drive, though.

 SimpleTech SimpleDrive 500GB ($89.99)

Pros: Pretty inexpensive for a good-looking 500GB drive, designed by Pininfarina of Ferrari fame, one-click backup and capacity meter on the top of the drive, includes 2GB of online storage through Fabrik.

Cons: Some customers reporting DOA drives or drives dying after a few months of use. Hopefully just a brief QA issue that’s been cleared up by now.

More info: Perhaps the best option when you factor in the one-click backup, online storage, thoughtful capacity meter, sleek design and lower price than competing models.

Mozy Online Backup ($60 or less per year)

Pros: Secure off-site storage, no need to purchase or maintain hardware or worry about drive crashes, relatively simple automatic backup, unlimited storage, can pay for it monthly at $4.95 per month.

Cons: Long-term costs end up being higher than buying traditional drive (storage is unlimited, though), can only be used with one computer – adding computers costs another $4.95 per month, much slower than having an actual drive connected to your computer, people concerned about keeping their files online should look elsewhere.

More info: This is actually the option I’d recommend to just about anyone. Mozy is easy to use, cheap to get into at $4.95 per month, and you don’t have to worry about setting up an actual, physical drive and hoping it doesn’t crash.

Storage is unlimited and you can set the software up (PC and Mac) to automatically back up certain important files and folders. Your files are backed up online, so they’ll copy much more slowly than if you had an actual external drive connected to your computer. Plus, as a backup service, it’s not great for actually keeping files for you to access as easily as you could with a conventional drive. So if you need MORE space, then you’ll want to check out an actual drive. But if you want to make copies of what’s on your computer’s hard drive, Mozy is a pretty good, simple, inexpensive option.