Check some options to buy online:
If you are looking for DIY kits, tools and some supplies, my ETSY shop is your best choice:

Amazon recommendations

If you are looking for supplies that you can't find on my shop, I'm sharing below some of my favorite products to use in cartonnage and bookbinding and that you will find on Amazon. 
This page contains affiliate links to my Amazon Recommendations. This means that any purchases made through the links below result in a small commission for ColorWay Arts. Thanks for your support! 

Chipboard 50 pt

Chipboard 100 pt

Chipboard 80 pt

Comic book board

Acid free glue