Right now there are 70 deals from Amazon Resale, formerly Amazon Warehouse Deals, in Books › Engineering & Transportation › Engineering › Mechanical. These are inspected returns and open-box items that Amazon sells and ships itself. WarehouseHunter puts each one next to its current new price, so you can see what you save at a glance.

Every item is a one-off, so the stock moves all day and new deals keep arriving.