Sticking to a budget for any reason can be challenging; sticking to a budget while traveling is even tougher. I am, and probably always will be, a budget traveler. These are the apps I have on my phone that help me keep track of my finances and stay within my tight, backpacker budget.
For years I traveled internationally with the bank account that I grew up with, just a standard national US bank. While traveling internationally I would get locked out of my account countless times and have to spend forever on hold trying to get access to my account again. The bank account had crazy high bank fees for trying to withdrawal money internationally and did not even reimburse me for the ATM fee. I was spending a ton of money to just have access to my money abroad. While I was planning my most recent, big international trip, I decided I had enough of trying to deal with the nonsense and switched to Charles Schwab. This is hands-down the best bank there is for travelers.