I have included two sites for you to read. The first one is concerning an alternative to the "Citizen United" Supreme Court decision--Cooperative. Jim Hightower discusses a fine way that already exists and may be the common man's way to avoid corporations.
The second one is "Purchasing the President: the 2012 Super-PAC Mega-Donors. Great article about how the corporations are using the power the Supreme Court gave them. It explains limitations and amounts. Great articles in Common Dreams.org.