Can I use the expression "what do we owe you" only in informal way?
Native speaker’s answer
Rebecca
In English, formality and informality really doesn't matter as it might in other languages. You can say "what do we owe you" to a complete stranger at the store and it would be just fine. If you want to sound a little more formal, you would say "how much is it?" This is a little more formal than "what do we owe you," and can be said to someone you are familiar with or not familiar with.