Split the Cost
Have you heard of the decoy effect? Here’s what it is in a nutshell: at McDonald’s, the cashier will try to get you to embiggen your drink order. You want a medium coke, they’ll offer you a large coke at only a 20¢ increase. Sounds good on paper, but in reality, they’re playing you for fools.
What you can do instead is dine-in and get unlimited refills with your small drink cup. Alternatively, you can split a large soda between two people—just ask for two small cups before speeding away from the drive-thru window. After all, a large soda is much too large for a single American to drink in one sitting.