I will give you my experience - which is my recommended method not only for trailers, but any large purchase of a vehicle as well.
Last fall I ordered a new trailer. I decided the configuration I wanted, then I called every dealer in 4 states and had them email me a quote. I took the lowest quote to my local dealer (also via email) and told them I'd buy through them if they could match it. They came within $500 of the lowest offer (which would have been the pricetag for me to pick it up a few hundred miles away), so I went with them.
The Sticker Price was $46,600 (which included $1000 bogus dealer charge). I ended up buying it for $29,600 out the door. That's >36% off of the sticker price. A little less if you discount their bogus dealer fee.
If you buy one off the lot, I doubt you will get such a deal, but with patience (took me about a week to get all the quotes, and another 9 weeks before the trailer arrived) and tenacity you can get a very good deal.
I would not negotiate with them face to face. I hate negotiating with salespeople and would too easily lose my cool and walk away. That's way too stressful for me. Instead, it was almost entirely via email, so I have the whole thread in writing. When I finally met them face-to-face it was to come in and pay a deposit on an already negotiated price. No BS, no bickering, no stress - best price.
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