Nobody carries cash anymore. How would you even fit boring green currency into your trendy new wallet? Nope. We live in a plastic world now.

There's only one small drawback to using cards for everything: the veritable mountain of debt associated with reckless credit card usage. 50% of college students have four or more credit cards and collectively owe around 30% of their income in related debt (source). Yikes.

So why don't you pay yourself a small cash allowance every week, and save the rest of your income for later? If you do accrue credit card debt, be sure to pay off your balance as quickly as possible. 

Oh, and when your college team wins The Big Game, it will be tempting to charge a huge pizza for your entire dorm to share. Just don't do it, dude. The moment of glory will fade quickly, but your horrifying debt will not.