Kash's wife lists specific items that are missing without being paid for. But they only have a regular register with a few item groups. There's no way to see what's precisely been sold. Also to check this, she'd have to do a full inventory of the store.
Throughout the first season, there is a chalkboard on the back of the front door at The Alibi Room advertising $2 Happy Hour. "Happy hours" have been prohibited in the state of Illinois, specifically in Chicago for almost 10 years (235 ILCA 5/6-28 aka "The Happy Hour Law").