Ergonomic Mice

I am currently looking for a new, inexpensive three-button mouse I replaced 10 years old, trackball mouse and it seems so many brilliant key "7" mice do anything. The only problem is that the educated people who want to use his right hand on the computer, and I left handed.do you know any mice that are either neutral or ergonomically designed to fit the shape of the left hand? If the mouse is on newegg.com, it would be good.