I've bought a fair amount of used laptops - for around $100-$150 each - on eBay for real, paid development work. For $300 you'll come out great. Any ThinkPad w

I've bought a fair amount of used laptops - for around $100-$150 each - on eBay for real, paid development work. For $300 you'll come out great. Any ThinkPad will do, but look it up on thinkwiki.org first. There's a huge variety of these machines and they're all pretty solid. You can pick your flavor. I tend to optimize for being lightweight, high RAM, 64-bit. Make sure you get one with a built-in WiFi card and reasonable battery life. All this will be in the item description.