Exercise from home

This 2010 model of treadmill is actually on sale online. I need to show to the husband since we are really planning to buy one for our home use. He's been very busy with work so he really cannot find time to go to the gym during lunch breaks or even after work. So we are thinking to get a fitness equipment instead so he can still exercise even if he's home.  Would you have any suggestions or tips on how to choose the right equipment particularly treadmill?  Do you think it's price of $600 is a good deal already?