I used to spend about $150 ~ $200 in Michigan on illegal fireworks, but its been a few years since I've purchased any.
There was a little town near where I lived in Michigan who had 'legalized' the sale of fireworks which were prohibited in the state provided that the seller obtained a permit from the town and the purchaser signed an agreement to the effect that he intended to transport the fireworks out of state and not resell them or use them in Michigan.
So for a few years, until the Michigan Attorney General got word of it and directed the Michigan State Police to start cracking down, you could get any kind of firework legal under federal law in this town.
Even after, it wasn't hard to find people peddling stuff. This Greek guy owned a gas station down the road, he brought back a few thousand dollars worth of fireworks from Missouri or where ever and sold them out of his garage to people he knew.
Then I got adventurous and
decided to make my own fireworks. Since I had 'experimented' with stuff like
rockets and mortars ever since I was a kid, it seemed like the logical thing to do. ;-)
But that was when you could order just about anything you wanted with a copy of your driver's license and a signature. Now, of course, this kind of thing is frowned upon by the feds and you might get a visit from the BATF for ordering chemicals through the mail. Ahhh, yes, I think they call it "progress".
My favorite was a "ground cake" of aerial repeaters, 49 1-1/2" tubes bundled together in a 7x7 arrangment, each tube containing one aerial shot. Each shot was composed of six colored stars, some glitter, and a powerful flash report (more powerful than any of the commercially produced cakes).
Its a real hell raiser, guaranteed to summon the police. One year, while attending the City of Saginaw's fireworks display, about 30 minutes before the display began, I [covertly] climbed to the top of a training tower use by the Saginaw Fire Department, placed two of them at the top of the platform about 50' high, lit them both then scurried back down that platform like a banshee to get the hell out of there before they started. I hurt myself climbing back over the damned fence but it was worth it.
Those things went off and you could hear the crowd screaming and cheering all the way down the river. It seemed like they just went on forever. Of course there was about 20 cops swarming the area immediately after but nobody saw who did it because it was dark, and I wasn't about to confess. heh