Newegg offers the refurbished Logitech G510s USB Gaming Keyboard, model no. 920-004967, for $37.99 with free shipping. That's $10 under our September mention and $42 less than the best price we could find for a new one. The keyboard features 18 customizable "G-Keys," 6-key anti-ghosting, game mode (which disables the Windows key), 3.5mm audio output, and custom color backlighting.
A 90-day warranty applies, but it's unclear who backs it.