Have you ever bought TV time for a campaign? I can cost thousands of dollars for a 30 second commercial in prime time. In big markets it would be nothing to spend 50+K a day or more on ads just hitting the major local TV stations.
Multiply that over a couple of months and it ads up quick. It takes alot of repetition to reach alot of people to make the message stick, not to mention defending attacks from the other side.
This doesn't even account for radio, newspaper, mail, and internet, plus campaign supplies like signs and brochures, and staffing.
Sorry, but it takes $$$ to elect people. Don't like it, don't play the game.