Other World Computing discounts a selection of used Apple Mac Pros, with prices starting at $649. Plus, all orders qualify for free shipping. Each item is covered by a 90-day OWC warranty. Note that for some models, available quantities may be limited. A few best bets, with comparisons to used units:

• Used Apple Mac Pro Quad 2.66GHz Xeon Workstation for $689 (pictured, low by $57)
• used Apple Mac Pro 8-Core Xeon 2.93GHz Workstation w/ 16GB RAM for $1,549 (low by $45)