Of course, Augustus could only spend what was raised. There's a difference from today, but I'll leave tax matters for later.
Think too what some Roman emperors -- say, Nero or Caligula -- could do if they had today's technology. You won't have to tretch your imaginations much. There's a story about White House dossiers. Could it be false or inflated? Sure. But given the hubris of the current Administration there's not a lot I wouldn't believe. Makes one almost sentimental for the Nixon administration -- itself not opposed to an enemies list -- and we have more than three more years of this.
White House keeps dossiers on more than 10,000 'political enemies' (Doug Thompson, Capitol Hill Blue)
Link via Jordon Cooper.