I have done a little bit of powder coating at home, on underhood brackets for my car. Haven't done anything on the trailer yet, because I don't have a trailer yet!
(I'm all talk, I know!)
Harbor Freight Tools sells a powdercoating setup that's usually like $99.95, but once in a while goes on sale for like $59.95. You'll need an air compressor, but not much of one, because the PC gun only needs about 8-10 psi. When you get the gun, get a couple of spare cups, and a couple of spare in-line dryers, too.
You just hook it up like it makes sense, and away you go. You can get powder from Eastwood, or off eBay, in like a zillion different colors.. There's probably cheaper places if you look around.
You do have to have the part pretty much down to bare metal, and clean at that. I used my trusty bead blaster, but a serious wire-brushing would work, I'm sure.
One of the keys to PC is getting the part all ready to go into the oven before
you shoot it. I just hang it on a piece of coathanger wire, and then hang it all in the oven, wire too.
Ah, yes, the oven! What oven do you need? The answer to that question, as is so often the case, is another question: How big are the parts you want to powdercoat? In my case, I was doing small brackets, and I bought a toaster oven at the Salvation Army for the princely sum of about $6, and screwed some cup hooks into the inside top to hang parts on. Do NOT use your home oven, as the coating off-gasses a little while it's curing, and you will NOT like the taste, I promise.
The oven has to heat the coating to about 350F for about 15 minutes, just to give you an idea.
Take the part out, let it cool, and voila! You're good to go!
Email me direct if you have questions; there's also PC instruction hints on the web.