Hi,
Gran is absoulutely right about this (retired postal worker here), especially if the office is in a smaller town.
Sometimes, they (PO) can't even get the boxes they order, and are limited to small amounts at a time, so after recieving an order, they could run out in a week, depending on customer requests.
That's why I always order mine online, so I don't have to worry my little PO with trying to get boxes, since I am in there constantly mailing packages (and no I don't get a discount - I wish I DID).
You have to make sure and look over the checkout page, before you complete your order.
Their website is very misleading, it will say one amount on the page you put the amount you want to order in, but when you get to the order summary, the amounts could be very different (as was the case here), from what you thought they were.
Dawn