When looking for a new supplier, be upfront with your intentions. I explain to the manager that I will never bring the coins back, and only ask for a consistent, reliable supply. If they are fine with the task, then I open the account with a minimum $1000. I explain to them that I pay with cash when the order comes in essentially leaving the $1000 untouched. It might be a too much for some, but I don't need the $1000 in my budget so it is fine to sit there.