First of all, you can look for the retail locations of moving boxes. You can find a number of them online. When buying moving boxes, you are also suggested to purchase moving box bundles or packs to help you save some money. Sometimes, these include other moving supplies like bubble wrap, packing tape, black markers, and packing paper.
Additionally, you should check if all of the included materials in the offered kit will be relevant to you and if you will be allowed to return the extra moving boxes in case you were able to order more than you need. This way, you will not hesitate to order for more moving boxes since it is better to have extras than to run out of stock just when you are rushing to finish packing your items. Also, when ordering for moving boxes, make sure to verify the sizes of the boxes.