In many laser atom cooling experiments, Acousto-Optic Modulators (AOM) are used to modulate a laser beam frequency close to an electronic resonance of the atoms. Commercially available RF drivers for the AOMs tend to be expensive ($2k and above) and can also require supplementary equipment such as power supplies and amplifiers. This article presents a low cost, compact, re-configurable, and portable modulator driver system. This system can switch between two frequencies within a period of few hundreds of ns, while giving the user complete control over the frequency range and output power up to about 2 W. This fast switching allows to toggle a laser beam between two optical fibers which could be used for cooling, imaging, or optical pumping of the laser-cooled atoms.