If you plan to study abroad this year, relying strictly on cash and debit cards can be a gamble. Cash can easily be stolen. Debit cards can charge foreign transaction fees and don't have the same protections as credit cards. Rather than relying on cash, consider using credit cards responsibly for your overseas spending.
Here's the problem: Once you get paid, your money has to go several places at once. Bills need to be paid, credit card balances need to be settled, groceries need to be bought, perhaps even some nonessentials, too -- and, in all the shuffle, the money that you should be saving becomes your discretionary income.