How do i ask out a bank teller?

Theres a bank teller that i like alot.She looks about my age maybe a little older.I would really like to ask her out but iam pretty shy.She dosent have a ring on her finger so i dontthink she is married.I was going to ask her out one time but i only had 40 dollars in my acc so i thought she would probably say no,since iam sure she would see that.Any advice on how to ask her.Or if i even should?