Lenovo discounts a selection of laptops, desktops, and tablets during its Dads and Grads Sale. (Discounts may be applied by coupon codes that can be found on the product pages; otherwise, the prices are as marked.) Plus, all orders receive free shipping.
A best bet is the Lenovo ThinkCentre M73 Core i3 2.9GHz Tiny Desktop (pictured), model no. 10AYCTO1WW, for $554.80. Coupon code "SAVEMORE" cuts it to $504.80. With free shipping, that's $50 off and the lowest total price we could find for this configuration. It features an Intel Core i3-4130T 2.9GHz Haswell dual-core processor, 4GB RAM, 500GB 7200 rpm hard drive, DVD burner, 802.11n wireless, USB, and Windows 7 Professional 64.