Here are the fireworks I bought from Sainsburys.
A Standard 'Limelight' selection box and a Standard rocket pack, both at 29.99UKP
The rockets don't look bad and some of the selection box looks OK, but the fountains are the usual cheat... Viz
Now I know they would say the big box is to stop us poor helpless consumers from burning ourselves, but it's really just a cheat to make us think we are getting more than we really are...
Also when volcanoes are done this way it's not the same firework at all. Real volcanoes burn more and more fiercely as the get to the bottom, owing to the diameter of the burning composition increasing - this can't happen when you put a straight gerbe in a volcano shaped case.
Thank god this is only to supplement my own stuff!