not going to put a dent in the illegal fireworks trade, if you really want to you can drive to new mexico and buy them by the side of the road.
In NH all fireworks are legal. Even the big ones like they have at municipal shows.
The best part is the stores are all located within a stones throw from the MA border. In MA, all fireworks are illegal.
The town of Jaffrey, NH actually has the best fireworks show around because it is the home of the Atlas Fireworks factory. People come from all around NH & MA to watch their show in Old Jaffrey Days in August.