Replying to Free stuff, courtesy of the US government

First off, I have done this, it is proven to work.

On here you can get anywhere up to 500 card board boxes per order, shipped to your house. The boxes come in all different sizes.

You can also get roll's of stickers too (up to 2200 per order)

So, if you are looking for things to do this summer order these and make a castle. I suggest getting the stickers to hold the boxes together.

LINKS:

Stickers- http://shop.usps.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10152&storeId=10001&categoryId=11825&productId=11653&langId=-1

Classic boxes:
http://shop.usps.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10152&storeId=10001&categoryId=11825&productId=11697&langId=-1

For more sizes choose view all on the side.