Also keep in mind the exchange rate for that country you are headed for to ensure accurate expenditure
This is one. Better to go there if the exchange rate is high. One factor that makes it look expensive to travel are those travel tour packages.
Much better to travel on your own with DIY plan. And when you're already on the itinerary, if it's possible to cook I agree, do it. Don't spend too much with restaurants unless you're too picky or you can't cook.