Yeah, the $2 for X deal is a gimmic to increase sales. It’s the company saying “I am willing to sell these cheaper if it gives me an extra sale.” But by applying that sale price to customers it didn’t apply to, essentially you just stole a dollar from your employer every time you sold an energy drink.

I’m personally pretty forgiving of something this petty when done by someone making an unlivable wage, but it’s still theft.

It's a very valid reason to fire you. You'll most likely get caught when the inventory starts to be way off.

Personally I don't care and I don't really think it's THAT unethical, but it is definitely theft. So be aware if you pull little tricks like that in the future. If you get caught, you'll DEFINITELY get fired and your employer MIGHT press charges (and they would win).

It might be more obvious if you increase the volume.

Immagine that your employer has instructed you to sell 1 bottle for $3, but you can sell a whole pallet containing 500 bottles for $1000 (coming out at $2 per bottle). So you ring up the whole pallet and pay it off over the next few days by adding $2 to the cash register and keep $1 for each sale. Over those days, you have made one single sale of a pallet, while pocketing $500.

The work hours which was meant for you to generate sales of $3 bottles has been reduced to effectively selling $2 bottles, while the remaining expected value ended in your pocket.

As others have said, I don't really care about big corporations losing out on some money, but you are 100% stealing when you reduce the expected sales value and pocket the difference during your work hours.

Per https://solink.com/resources/top-types-employee-theft/ it’s basically “Skimming”:

This popular POS employee theft scam occurs when an employee charges a customer full price but takes a little cash out of the total for themselves. This may result in telltale cash register imbalances, or, it can be more complex, like using coupon codes on a customer’s purchase while still charging them full price and then pocketing the difference.

Your implementation sounds pretty close to the coupon version.

Are your bosses ever going to notice? Unlikely. And if they did they’d probably fire you at worst, rather than press charges.

Now, that said, if your manager or employee handbook or any other source of authority at your job says it’s okay, then it is (excepting, of course, if they explicitly tell you it isn’t) - but that’s because it’s a benefit your employer has given you rather than one you’ve taken.