I've always created an Excel budget every semester to make sure that all of my school and living expenses are covered. However, I'd had quite a few surprises come up like needing new tires, a miscellaneous fine, or a special event. After being unprepared the first few times, I decided to set up a separate online bank account just for my emergency/unexpected fund. I keep a minimum of $1,000 in it all time and let myself forget about it since it's under a separate account that I don't regularly check. It's earning interest and I know that I'm covered if something I didn't plan for comes up!