Bottles with refundable deposit for the wedding

This idea came to me by thinking of how the wedding couple could possibly have the most work. You have to collect bottles for quite some time, best would be plastic bottles. The money gift is now, that the wedding couple has to give the bottles with refundable deposits one by one to the shop in order to get the money. It will take its sweet time, I am sure… And the shop owner will be very happy!