There are a lot of very respectable laptops available (off-lease and such) for relatively cheap.

I picked up a ThinkPad T420 a few months ago on eBay for, IIRC, $180. For $250 all in, I had a nice i5 laptop w/ 16 GB of RAM and a 120 GB SSD. I didn't need it and don't really use it for anything but it's great when I need a spare or somebody else wants to use it. It could easily serve as a great primary machine for an average user (i.e. e-mail and Facebook / web browsing), though.