One can find many companies when looking for custom packaging boxes.
But picking the right service provider is complicated.
Things to consider:
>> Print & Paper Quality
>> Mini Order
>> On Time Delivery
>> Hidden/Delivery Charges
>> Service Support
>> Production Status etc

Most of the customers didn't find the difference between the actual printing company and a print broker. It's always good to have proper research on TrustPilot reviews, Website, and Google reviews.

These are the actual printing websites I had used before, and I am satisfied with the print quality & service both in US & Canada.
https://www.newprint.com/
http://moo.com/
https://www.newprint.ca/