A two for one deal right there.

Ya, trying to save someone money means they are definitely a very rude and horrible person.

The problem with halitosis is that people who have it are often (at least partially) unaware of it until someone tells them, and most people are too chicken to tell them about it because it's seen as super shameful or hurtful, but when it's just too bad damn someone's gotta say something ! Plus it can often be fixed with appropriate measures, so people shouldn't be left clueless about it...

How is it saving money? That person was an ordinary person buying mints - but the cashier decides to comment on their breath, assume they are planning to have a girl over - based on the fact that that person is buying a pack?! They are saying something in a cruel manner, in public to a perfect stranger. If they wanted to help Op they could recommend some and say 'these are really good' or they could pull htem aside some point if OP shops regularly, not humiliate them like that. They might not have halitosis - we don't know, but regardless, the cashier was very rude in how they acted. You don't tell someone with dandruff they need different shampoo if they want to impress someone, you don't say to someone overweight they should swap that sweet/burger for an apple if they plan on getting laid. It is none of the cashier's business.

There was nothing rude about this, it was just a simple suggestion based on observation. If you want rude, I can give you a list of things that would actually be rude in this case, but I can't list them here because I would be banned...