For car/trucks it is the norm to haggle over the pricing but does this extend to enclosed trailers? My internet research was always pulling up RV trailers and not enclosed cargo trailers. Anyone willing to offer any insights into their trailer purchases?

It couldn't hurt to try. I don't think you'll see 30+% like on RV trailers but there could be something.

Last time I bought a 6 x 12 utility trailer (15 years ago), think all I was about to get was a spare tire thrown into the deal.

With regard to RV's, I once was told by a former finance guy that they have a minumum of 50% markup and there is lots of room to negotiate price. Would think that cargo trailers are similar.

I have a 6x14 enclosed cargo trailer that was purchased new. Looked at
everything available in my area and it was pretty much "the price is the price."
Add that the dealer has five or six different levels of quality so when you chip
on price, they chip on quality.
The used market was very slim pickings, either rusted out junk or used but priced
at nearly new. I think it's probably the case that used trailers in good condition get snapped up by friends or neighbors pretty quick.

I don't know but it never hurts to ask, all the dealership can do is say no

I did and it was a bit more than 30 % off.

If there's more than one company vying for your business, there's always room to negotiate. As noted above, margins are likely to be much smaller than on new cars, but my bet, there is a little wiggle room in there if you're willing to try.

I think it probably varies from dealer to dealer. When I bought a cargo trailer a few years ago I bought it from the manufacturer in Kentucky. It was worth the 3 hour drive each way as I used it for two years and sold it for close to what I paid for it. You can view the different manufacturer’s websites and see if any of them have a facility within a reasonable distance. If I’m not mistaken most of the various trade names are made by two companies. Good luck!

You can haggle over pricing on anything but not usually at big box stores. I have made cash offers to get lower prices. It works.

Haggle. I got about 25% off from a local dealer after I found the same trailer available online. This one was build to order so it wasn't sitting on his lot. Just remember, cheaper is usually, well, cheaper. In hindsight I think I would have spent a little more for better quality. Overall it is holding up well but I constantly have sheet metal screws coming loose.

A friend of mine owns a welding company and one of their specialties is trailer repair. Everything from the small utility type all the way up to tractor trailers. His family also owns a trailer dealership with a service department, so all of the welding work finds its way over to him.

The moral of this story is that there are a lot of junk trailers out there. I see them in his shop and hear all of the horror stories. I would inspect the construction of any trailer I was looking at very closely, and see if you could find reviews from long term owners to see how they hold up. It seems that many of these look great on the lot but then start falling apart the second you start using them.

For this reason you may also want to make sure your dealer is capable of performing any warranty issues you may face. If your dealer doesn't have the means to work on them you may be forced to return the trailer to the manufacturer or some other third part for any repairs.