What kind of brush best suits my dog?

I have a beautiful Australian Shepperd/Beagle Mix who sheds like crazy! He has hair about 2" long on the top of his back and hair 1" and shorter everywhere else. He sheds all the time, but more in the spring. He also has a very thick undercoat that seems to always be falling out as it gets warmer. We brush him nearly every day with a normal brush, but I am wondering if there is a better brush out there. I have seen the FURminator deshedding tool, i have seen undercoat brushes, deshedding knives, but I just don't know what is best. I really don't want to spend much more than $15, but I will get whatever I need to get results in reducing his shedding. If there are any groomers out there that can help me, i would greatly appreciate it! If you need more info, please e-mail me. Thanks!