One option is to publicly fund candidates equally. In such a system someone could apply to run for a position, the position would require a specified amount of people to nominate that person, if that person is nominated they get a grant that covers their campaign costs. The amount wouldn't be excessive so campaigns would look very different than they do now in places like the US.
Another option is to limit campaign donations from any individual to $100 total. This would force politicians to put effort into building a grassroots campaign while keeping big moneyed interests out of the process.
When politicians get into a position of power, they should be paid enough that they're firmly in the upper middle class, so they're comfortable and less likely to accept bribes, and they should not be given any opportunity to accept bribes or profit off of their position in any way.
Potentially losing your job would be part of the risk/sacrifice a potential candidate would have to accept. Yes, it would be difficult for someone living paycheck to paycheck to do this. Ideally, election reform like this would go hand in hand with economic reform that leads us to a society in which much less people are living paycheck to paycheck. This could happen easily if we start electing real people instead of rich people only.