Office Depot has the Microsoft Natural Ergonomic Keyboard 4000 for a good price.

Cnet gave this item a rating of 3.5/5.0

Pricegrabber Price : $34.99 ~ $81.97 Shipped

1. Click here to go to Office Depot
2. Search and Add 283736 ( Price : $44.99 )
3. (Recommended) Add $5.01 worth of goods to get free shipping or you can pick up in-stores to save on shipping
4. Rebate Price : -$15.00 ( Exp : 09/06/08 )
Final Price : $29.99 After Rebate