You can also pick up a Thinkpad T400 laptop on ebay for about that amount. (Has absolutely crap video hardware, but plenty good for web development and educational purposes.)
I have a couple T61s from Ebay that I got for my kids. I've been using one of them for some development work, and I've been surprised at how well they work for that purpose --- as in, I could easily use one for my day to day work. Put an old SSD in one, install Linux, and you have a very nice machine.
I bought a Thinkpad x220 tablet off ebay as a "poor man's Cintiq" and put an old SSD in it. The thing is like a developer Swiss Army Knife. I can use the very nice keyboard for real programming work. I can use the Wacom stylus for pixel art and graphics. Makes me think that Apple is aiming at dominating the common-person's "workstation" form factor, while Lenovo is aiming more squarely at guys like us.
For value in a used linux laptop nothing beats an Acer C710(~$60+)/C720(~$100); they'd beat the T400 or a 2.8ghz P4 (by a mile in total system performance), with an SSD and HDMI output, all while giving you >6hrs battery life and USB3 in the case of the 720. IIRC the iGPU's in the T400 era don't do webGL.
