If Sanders were to be nominated, he would not be able to raise enough cash via private donations. The stakes are much higher. He'd have to go to more traditional sources.
As to who lies: All politicians lie. Clinton and Sanders have similar Politifact (fact-checking) records. Trump's is far worse. So the suggestion that she is more of a liar than Sanders, or any other major political figure, is not correct.
I agree, however, that Citizen's United and the likes of the late Justice Scalia (who also helped make "W" President) really screwed up campaign financing. However, it has been shown this year that those with the most money aren't always the victors. On the Republican side, Jeb spent the most money, with little to show for it.