Newegg offers the Microsoft Desktop 800 Wireless Keyboard and Mouse, model no. 2LF-00001, for $19.99 with free shipping. (Amazon has it for the same price for Prime members.) That's tied with our July mention and the lowest total price we could find by $5. This set features a wireless range of up to 30 feet; the keyboard includes hot keys and the mouse has 1,000 dpi.
Newegg offers the Microsoft Natural Ergonomic Keyboard 4000, model no. B2M-00012, for $19.99 with free shipping. That's $5 below our mention from a week ago and the lowest shipped price we've seen all year, outside of refurbs. (It's a current price low by $10.) This USB keyboard features a split-key layout, programmable multimedia keys, and an integrated palm rest.
Newegg offers the Microsoft Sidewinder X4 Keyboard, model no. JQD-00001, for $29.99 with free shipping. That's $10 below our July mention and the lowest total price we could find by $16. It features anti-ghosting capability, automatic profile switching, and programmable macro keys.