This episode goes over how much the federal government spends per person in broad categories. I also suggest allowing people to have a binding vote on a federal budget by broad categories that changes the budget by up to 5%. If Congress wants to spend MORE than what people approve, they need 2/3. If they want to spend less, a normal vote will do.

The guardrails would require that a person has some idea of the amount spent in categories--open book test--and that you can't vote to skip interest on the debt or wipe out mandatory spending programs.