The travel item is very complicated to budget, since the costs are not known in advance. The main item of travel expense is the aérea, as of today, there are no flat rates, therefore, the budget is approximate.
The main factor that a traveler has to take into account is the purpose of the trip, since in many occasions, to simplify a procedure, or to save some money, travelers often resort to apply for a different visa than the one they really need. In most of the occasions they opt for a tourist visa. If the authorities of the country are not very rigorous, it can serve to get out of the way and be able to obtain authorization to enter a certain country.