Newegg offers the refurbished Haier 8,000 BTU Portable Air Conditioner, model no. HPY08XCM-LW, for $179.99 with free shipping. That's $55 less than the best total price we could find for a comparable new one. It features a 24-hour on/off timer and auto evaporation system.
A 30-day warranty applies, but it's unclear who backs it.