I no longer make powder boxes due to the high cost of materials which consequentially pushers the retail price up to what i consider unreasonable/
However you may find it economic to make one for your own use.
Plans for making Black powder boxes
If you want to have a go at making one yourself here are the plans.
A storage box to hold 5kg of black powder or black powder and smokeless powder in 10 containers. This design complies with the MSER Guidance.
I had a request to make a powder storage box to hold black powder in old 500 ml plastic milk containers. If you want to do this here are the plans. Decant at your own risk. This design complies with the MSER Guidance.
Here are the explosives labels I put on my boxes.
For help or further information e-mail