I always buy the business grade machines, its like buying a truck instead of a cheap car, they are built to last.
+1. Especially on last-minute clearance. A demonstrator or gently used business machine will outlast the shiny biodegradeable junkers by a factor of five.
Business laptops. Big companies buy them by the hundred, buy 10 non working for a couple hundred dollars and have a decade or more of spare parts.
Or even get them free at a public drop-off (snagged them for parts but what do you do when they are all perfectly functional?). ThinkPads are especially modular and designed to be refurbished endlessly. And the classics like T60s, T61s, T400s are quite capable if you can bump up the RAM and are generally indestructible otherwise.