If I buy a simple laser diode module such as the ones shown here: http://www.calpaclasers.com/laser_diodes.html Do I need to buy a laser driver power supply for the laser, or can I just plug it into a 3 volt battery source?

Thanks. :?

Just connect it to a 3 volts supply, have fun! However, it is the same as a laser pointer, which you can buy cheaper.