The thing is, these days with social media, does it really take all that much money to run a campaign and to reach out to people?
I think you can run an effective campaign for a fraction of the cost that politicians spend, of course it would put a bunch of useless political consultants out of business.
Which makes me wonder just how much of his personal fortune has he had to use to get to this point? Maybe he's spending far less of his money than we assume.
Also, as his momentum builds, I would think that a lot of donations will start flowing his way.