I'd be ok w small donations but also a public fund for donations. I actually have my own idea for govt that I shared a few times in the past. In short though, I agree w elections but they should all be extremely small. You win your very local election first and you may be voted by your own legislative body to represent it at the next higher level.
You win 7 or so of these very small and secret ballot elections involving only people that know you and keep advancing and you could be president.