For example, back in January 2014 I purchased a refurbished Dell Latitude 3540 which has an i5-4200u, 1080p screen 8GB of RAM, 1TB HDD and a Radeon HD 8850m for somewhere between $475 and $500. It was purchased from ebay with some who had a 98%+ rating and over 8,000 feedbacks. The laptop was refurbished by Dell and at the time had a 11 month warranty. If I purchased it new from Dell it would have cost me around $850.
If I had search for that laptop in December 2013, I could have purchased it for $350 from Dell's Outlet Store. Apparently, the seller bought these laptops in bulk (he was selling something like 30 of them), and then listed them on eBay.
I have been happy with my purchase, though I am looking to replace that laptop by sometime next year.