One place that offers a wide variety of boxes is the Post Office, and places like Walmart goes through quite a few of them on a daily basis. More often than not, places like this will let you have these boxes. One bit of advice that I keep in mind is to stay away from boxes that had food in it. I do this because the smell of the food that was in the box could potentially be there still and attract bugs to the box.
But what happens if you have a box that you want to use that has a ton of writing on the outside? This is actually very simple, and all it takes is some mailing tape and a pair of scissors.
The first step is to cut the top and the bottom loose, like this: