Based on the context and the answer, generate a question. 

Context: At the parking structure Viv got a lot of the new dollar coins after paying for parking . They 're very shiny ! We kept M company while she paid and then we off to the vehicles . I was riding with Viv and we were going to pick up Joe at Vienna Metro .

Answer:

Because she over paid in cash .



What may be the reason for her getting dollar coins back ?