Do you know how many snacks and drinks you buy every week? Do you find yourself running low on funds on a regular basis?
Know where your money is going. Get an old-fashioned paper check register from your bank. (They're free!) Keep it with you and record every penny you spend. Include the date and description of what you purchased. Don't forget to include your regular bills like rent and utilities. Also record any money you loan to friends. At the end of each week, add up you expenses. Look back at your records and find where you can cut back. It's simple and easy and only takes a few seconds when you buy something. You and your future are worth it!
I'm sure there's an app for this, but there is something about the reality of paper. It will also make you think more about buying stuff if you have to write it down. Just the process of tracking your purchases on paper will keep you from spending as much!