No, they would not work as a shipping box. You would need to put them in a bubble envelope or a mailer.
In the future, I will be getting small mailing boxes that you can ship 1st class mail. Postage on them runs about a buck and a half and the boxes will sell for something like 50 cents or so.
You can get the large video mialers from the US Postal Service for free, they will even deliver them to your door. Then you put them inside a flat rate priority envleope and you can ship them for 4.60 which includes delivery confirmation if you do your postage on line.
Al @ THO