Pay for your dates with cash and date within your means. If you bank online using a shared computer, be sure that your sensitive information is cleared out after you complete a transaction. We often see these free trials turn into charges on a credit card. If you want to avoid using your credit card, lock it in a safe place. If you have a car and others use it or expect you to drive them places, ask them to contribute for gas and other costs.
Bad checks carry a high price tag.
You pay the bank the check it is written from, the bank it was deposited in, and the merchant it was presented to. A late payment today will remain a part of your credit history for seven years. All of these things become more difficult with blemishes on your credit history. If you find you are stressed out about money or debt, talk to someone. The student life office is a great place to start.