Kevin O'Leary has invested hundreds of thousands of dollars in small businesses over the course of his tenure as a star and investor on ABC's "Shark Tank."

But there is one business to which he refuses to fork over his hard-earned dollars: coffee shops.

"Do I pay $2.50 for a coffee? Never, never, never do I do that," O'Leary tells CNBC Make It. "That is such a waste of money for something that costs 20 cents. I never buy a frape-latte-blah-blah-blah-woof-woof-woof for $2.50." Instead, he makes it at home.

"I drink coffee, one cup every morning," he explains. "It costs about 18 cents to make it, and I invest the rest." (That probably means he's not a fan of $7 avocado toast either.)