Not sure if it worth mentioning as it may seem obvious but Staples seems to maintain a large inventory of used laptops. I assume they are mostly off lease. I see some very good deals come via their mailing list from time to time, usually when they have put a refurbished machine on sale. Recently, they listed some HP and Dell units with 3rd generation i5 processors for around $300. These are business class laptops. 

On Sat, Jun 4, 2016 at 2:16 PM, D. Hugh Redelmeier <hugh@mimosa.com> wrote:
| From: D. Hugh Redelmeier <hugh@mimosa.com>

| Off-lease computers from Dell Financial Services, but only when they
| have a sale (every month or two, discounts often 33% or better).
| Their most recent sale was for Victoria Day weekend.  By the nature of
| leasing, they are going to be business machines: unsexy but solid and
| not as cheap as one would like.

There is a sale this weekend: 33% Off all Dell Laptops, including Hot
Deals, with code 33LTWKND

<http://forums.redflagdeals.com/new-dfsdirect-ca-coupon-codes-1155678/35/#post26114895>