I have a logitech cordless freedom pro (the natural keyboard), ony using the keyboard though. I've had it for 2 years, havn't had to replace the batteries. Its radio not the infrared, works fairly well, range is about 20 feet. I love it!!!
edit: try ebay for a cheap one, check pricewatch too. Other than that I'm not sure, the logitech ones all run around 100 bucks I think.