I'm a little way south of Miami.
There are garage sellers around. Sadly, I haven't really checked them out yet. There is one local guy that I've bought from a few times, not sure that he's a member here, but I will direct him to this thread.

You can definitely find more garage sellers on Craigslist though. Hmmm, I know that there are some really great sellers down here too, but I'm pretty sure folks like
@joshporksandwic don't sell out of the garage... but perhaps he could better answer your question about garage sellers than I can. I'd love to know how it goes for you, and perhaps we can share future experiences.
My preferred LFS's are Ocean View Aquariums on Bird Rd., VIP Reef in Cutler Bay on 137th Ave, Reef Top on US1 down south, Blue Seas in Ft. Lauderdale, as well as Aquarium King also in Ft. Lauderdale. Aquarium King has given me the pleasure of showing me the back room and their great qt setup.

They are my preferred store for fish. There are lots of stores around, but these are where I've had good experiences.

There are also one or two that I would absolutely avoid, particularly one near to Kendall and 117th Ave.
The LFS's do run copper as far as I know. At least, I'm sure they do at a particular LFS, but I'm not sure about them all. I've noticed that most keep their inverts in separate systems though, and that's a sign of copper use to me.