You can drop the extra boxes off at any Post Office. While the local post office carries some of many sizes of boxes, some of them are only available online and are not available to the local PO. I Ebay a lot and when you order boxes through the internet they come in set quantities such as 10,25 etc. I take extras that accumulate that way to my local PO and they are glad to get them. Maybe one day you will need a certain size box and it will be there only if someone who has them and is not using them turns them in. I sense that many people are concerned about money spent on things like this or TV ads, etc. Know this - money spent on these things are but a drop in the bucket. The real money is spent on only 3 things, The Military, Social Security, and Medicare. Just my 2 cents.