It can vary widely depending where you are and the choices you make. My preference is to not budget at all and just have more than I need available. I am a cheapskate so I don't spend much, but I prefer to limit my spending by choice rather than because of a limiting budget for the trip.

Time is the same way. A trip is much more fun if you aren't worried about a schedule or budget. It is nice to have at least a week and a thousand dollars more than you actually need. That way you can just take things as they come. Too bad that is not always possible for all of us.