By Noah Higgins-Dunn

A vivid piece of financial advice from Shark Tank’s Kevin O’Leary slips into my mind every time I’m about to enter Starbucks: “Do I pay $2.50 for a coffee? Never, never, never do I do that,” he said in a CNBC interview. “That is such a waste of money for something that costs 20 cents.”

During those late nights at the library, cramming for an exam but struggling to stay awake, I’ll frequently sneak off for a tall Pike’s Place pleasure. I justify the $2.50 expenditure because, in my mind, the small cost is worth the reward.

Except Mr. Wonderful’s warning of never buying the liquid gold, but rather spending 18 cents to make it at home and investing the rest, sounds outrageous. Not to mention that’s coming from someone who works at a media outlet which rewards its employees with free coffee.

But O’Leary’s words still haunt me, and here’s why:

If I spend $2.50 on a regular cup of joe twice a week, which is one of the cheapest items on Starbucks’ menu, then I’m paying nearly $240 a year on coffee at one shop alone. When you’re young and your paycheck sometimes doesn’t surpass that mark, coffee becomes a noteworthy sunk cost.

Personal finance author David Bach calls this “the latte factor,” and it doesn’t solely apply to the world’s greatest beverage. (I admit I might be slightly biased.) Unnecessary spending can slowly eat away at your wallet in a variety of methods, not just on beverages.

So, I went back into my bank records and found spending, just like coffee, that trickled out of my account almost inconspicuously. Here’s what I found:

• Unnecessary subscriptions: One month an app is hot, and then it’s basically gone the next. Except, did you remember to cancel your subscription? I found nearly two apps charging monthly fees for their services, and without a watchful eye on my records, they were able to do it under the radar.

• Food, food and more food: Finding spare time to do anything is hard, especially when it comes to going to the grocery store. Except paying for Chipotle bowl after Chipotle bowl can become expensive. Think about spending a large chunk of time rather than small intervals to plan your meals, visit the grocery store and cook your meals at the beginning of the week.

• Uber, Bird and other lazy expenses: I get it, campus can seem far and you don’t want to walk today. That scooter is beckoning you from the sidewalk. Ridesharing apps make it easy and a split-second decision. Except how many times, including those weekends out with friends, are you actually using these apps? I went through my credit card statement for the month and found I’d spent nearly $40 on Uber, but most bills didn’t surpass $15. That’s about $480 spent over the course of a year. I think I’ll walk.

• Don’t fall for click bait: It’s hard to resist promo emails, but take it from an avid online shopper, do not click! You might think you need that sweater for the fall or that neutral tones are in this season so you must buy that jacket, but ploys like this are exactly what these companies want you to fall for. If you have a student discount, it complicates things even more. Remember: There will always be discounts in the future, so don’t fall for every single one that comes flying through your email.

And the kicker:  Creditcards.com reports that credit card interest rates have hit a recent record high average of 17.14 percent, which means that the little purchases you put on your card can really explode if you don’t pay it off every month.

Noah Higgins-Dunn is a senior at the University of Missouri School of Journalism.