If you need to supply your own boxes due to shortage of time or need of specialty boxes, they must be of a quality that matches the guidelines associated to this link.
You can purchase your shipping boxes either online or at any local vendor that carries boxes. Examples are the UPS Store, U-Haul, Lowes, Walmart, Amazon.com
*Moving boxes are not accepted as they are not double corrugated and tend break open in transit.
If you need a special box to ship a bike. https://www.shipbikes.com/buy/
Make sure you collect dimensions and final weight for the creation of Shipping labels.
Click this link to learn about overages and additional fees.