Where do they sell boxes for shipping?

A lot of companies provide customized boxes for shipping, but this won't be the honest answer. A lot of those companies do not actually exist, they are scammers. Then there are those do not scam, but they outsource your order to some real company, get away with your money and all you get is a bulk of substandard shipping boxes. Then there are those who delay shipments, apply a lot of hidden charges or provide poor quality boxes. I use PackagingBlue.com for my tees business and they are the ones I would like to recommend.