Is it rude when cashiers/sales people look to your wallet?

Has happened with them but to give a softer example a lady asked me if I wanted to buy a box of face masks before when I was walking. I did need some cheap ones and they were the soft blue ones I like. However since she was walking around with one box I figured that she bought too many or they were stolen. She said three dollars and I said I only have 2. I gave her the two and she said can I also have that quarter. I said I need it for the train and walked away.

Roo