To seek short-term satisfaction is human, and you couldn't get enough of it in college. Your spending habits would get out of control, and you might put yourself in a state of self denial. You're cheating yourself, as this should affect your focus on your coursework. On the other hand, you want to justify your action. Your (undergraduate) degree must be your top priority, but there should be days when you must give more than what you have. It won't be the case of your lack of resolve (or your unwillingness to get out of bed). You could end up resorting to junk food, even beer. (If you're a smoker, then packs of cigarettes must be part of your budget. Consider yourself lucky if you have generous friends.)
If you want to make the most out of your college days, then you must live within your means. You may not like the idea of frugal existence, as you deprive yourself of certain things when you need it. (A slice of pizza would induce you to write your essay, but you don't have spare money for it.) Deprivation can be looked in another way while you remind yourself of good things to come (while suffering from it). Whether you have well-to-do parents or coming from humble background, you need to learn the fine art of stretching your school budget. It's not something that your professors will teach you, but they can share their experience (if you can swallow your pride). You must learn the rest, which you can manage in a month or two.
What You Must Do During Your First Month
Tip 1. Rewarding yourself can change your habits. Don't ever think of long-term goals, which you're likely to break before Thanksgiving. It starts in small steps, so look at it on a monthly basis. A reward must be something that you love the most. It can be concerts (and you like to lose count of it). It can also be a Christmas holiday, if not a summer getaway. (You might want to talk to your parents about it.) You can let yourself down (and have a blast during a party). Behavioral scientists would describe a nudge as a change in an individual's traits after successfully completing a goal. It can be depriving yourself a Starbucks for a month or two, and the money you would save from it could be used for immediate expenses (in the university). The same money would enable you to watch concerts, if not organize a party with your buddies.
Tip 2. Live healthily. Sticking to a diet of fruits and vegetables may be a tall order especially if meat (or sugar) may be the only way to get yourself (to finish your assignment). It may cause discomfort in the beginning, but you'll reap the rewards in the long run. Think of how this diet can benefit your body, which will be under pressure during the term. Moreover, indigestion can result from your (sometimes) unpredictable schedule. If this won't be convincing enough, then think of the cost. There's no need to worry, as you can catch up with the empty calories during a get together with your friends.
Tip 3. You must watch out for your expenses. If you're living in the university (or near it), then it's likely that you must set aside a fraction of your money for the rent. And it must be your top priority. If you think that a part-time job can help you, then consider the distance. (Transportation expense can pile up at the end of the week.) Don't forget Christmas, as well as the birthday of your roommates and coursemates. Careful spending doesn't mean disregarding the other aspects of your life, one of which would be establishing a network after graduation. There's a way if you really want it.
Tip 4. Create separate budgets. It would be very foolish of you to believe that you can handle your money right away. It will take some time, but there will be a solution. You must plan your budget every month, calculating your estimate on daily expenses and unforeseen circumstances (that would require money). You can add another one for the one thing you love the most. (This would be your reward for the effort.) If you're incapable of mental accounting, then look for boxes where you can put aside your money. You may ask your parents for help, as they can put the cash in the bank. (You can get it when you need it.)
Tip 5. Spend less. If you don't have much to spend on something, then you would find yourself with money at the end of the month. It can take willpower at times, even commitment in the long run. This skill will help you during your first few years as a professional, as you can have your own place (or car) early on.
If everything else fails, then you must do the following
Ask for help. Don't be ashamed about it, as you don't learn the essential things on spending (or saving) overnight. Your parents won't let you feel miserable about it, but promise them one thing. (You have to be an exceptional student or else.)
British students can eat well at 3.50 pounds. It's roughly equivalent to 5 US dollars. It seems impossible, but it can be done if you shop around. It also pays if you can cook your own food.
There are apps that can remind you of your spending habits, but it might be better to do it the hard way. You can learn a new habit if you keep on doing it for three weeks or less. If you're motivated enough, then anything can happen. You want to end on a high note.