Amazon offers the Brother Wireless Monochrome Multifunction Laser Printer, model no. MFC-L2740DW, for $179.99 with free shipping. That's the lowest total price we could find by $20. It features 802.11n wireless, automatic duplexing (2-sided printing), up to 2400x600 dpi printing, and up to 32 ppm print speed.

A close price: Newegg charges $179.99 plus $1.99 for shipping.