Companies usually don't buy their laptops, screens and other hardware, but lease them from companies that then service the hardware.
When a company upgrades lots of the hardware is then sold by the leasing agency to the public for very favourable prices.
My off lease laptop is literally my three year old work laptop. It is a very sturdy HP laptop with 16 GB of ramm, a 512mb SSD and a pretty decent i7 processor. The body is very sturdy and the screen is excellent. I paid about 180 dollars for it.