Amazon offers the Brother HL-L2300D Monochrome Laser Printer for $39.99 with free shipping. That's $3 under yesterday's expired mention and the lowest total price we've seen. (It's a current low by $8, excluding the below mention.) It features print speeds of up to 27 ppm, up to 2400x600 dpi resolution, automatic duplexing, USB, and a 250-sheet capacity paper tray.
A close price: Newegg offers it for $39.99 plus $2.99 for shipping.