HELP!Follow

ok I have a serious question that needs answering. Why is that when i goto to buy something that says its costs 70 copper coins, it takes like 200 copper coins??
and on a similar note, when i goto bank money, and drag large sums into the Auto Bank box, it dissapears! i have a total of 45 copper coins in the bank from the 200 copper coins i dragged into it.. am i missing something here?? please help!!