Asus U: I'm not familiar with this PC, but Eisner, who generally knows what he's talking about, recommends it. The Asus U comes with the same processor as the Lenovo but a bigger hard drive and a bigger screen, which makes it heavier at 4.2 pounds. At $580 the Asus U is a full $1,000 cheaper than the MacBook Air.

Here's another way to save money on a laptop: Don't let it get stolen.

Try not to use a very conspicuous laptop bag. Better to carry it in a backpack than in a fancy nylon carrying case that tells bad guys there's something inside worth stealing. It probably won't do any good, but explain to your student that they should never ever leave their PC or Mac unattended in a public place.

Some laptops have a Universal Security Slot on the side of the laptop that can be used to connect a cable or alarm. The Kensington 64068F cable and connector costs under $40. Belkin makes a device that sells for around $20 and sets off an alarm if it's removed. Mark your laptop with an ID code. Companies like yougetitback and armortag make it easy for someone who finds your laptop to call an 800 number and get a reward.