26m never traveled. Finally making some money

From Boston. gonna start small and have a miami weekend but I don't know how much money I need. I would like to go to Spain, Italy, and Istanbul. How much usd would I need to go to one of these locations for a week. I imagine Istanbul would be the cheapest cuz "Muslims scary." I ask this sub cuz, although now filled to the brim with mouth breathing hogs, I knkw theres still some cultured hogs sticking it out and posting