Dell Home, via its Member Purchase Program, offers its Dell Bluetooth 4.0 Twisting Mouse, model no. WM615, for $33.24 with free shipping. That's tied with our mention from a week ago as the lowest total price we've seen. (It's the best deal now by $3.) It includes two AAA batteries.
Note: Dell's MPP is available to select groups, including students, government employees, military (active and retired), credit union members, and health care workers.