Currently a campaign for the Presidency requires around $1 billion in funding. This severely limits the ability of other political parties to contribute and compete in elections. The two party system is clearly flawed and it is becoming more and more evident that it end with the two sides at extremes on almost every issue.
Instead, lets create a general election fund. People can donate to this fund, and this fund only. The monies from that fund will be split evenly amongst the party nominees (1 nominee from each party).
People and organizations can do other things like volunteer their time to help a candidate, but buying an election through enormous campaign donations is wrong.