Kendon has been making trailers for a while. If the one you are looking at is the square tube/angle iron model then I think the asking price is way high. But if its the bent tube model as shown in the link above then $3700 is the current MSRP. I don't know what dealers actually sell for. Just a few years ago MSRP was $2800.
The model pictured features a wide loading ramp. Older models of the tube trailer included a minimal ramp under the folding tail. You could take the ramp off only with the trailer tail folded. Then it has to be transported in your tow vehicle.
I found mine used on Craigslist about 5 years ago. Owner said it had about 4,000 miles on it, mostly a trip from Arizona to Alabama. Since then I've been everywhere from Texas to the Carolinas, to Indiana, several times. At least 15,000 miles. Tires still look new.
Have had a couple problems. Mine spends a lot of time folded against the wall so the casters get used. Middle caster quit pivoting and the replacement I found is a might higher so it doesn't push around as straight as it once did.
The trailer lights are mounted on the fenders which are mounted on the unsprung wheels. Have had a heck of a time keeping bulbs from burning out no matter purchase of "heavy duty" with shiny nickel bases. Eventually I found two that work now I have LED replacements sitting ready.
The Kendon Dual Stand Up Trailer is very low and close to the road. The bottom front tubes suffer from a lot of abrasion from road grime in the turbulence behind your tow vehicle. I'm past due to take the wire brush to the rust, then cold galvanizer primer and rubberized undercoating.
Oh, and it will carry two Goldwings as if there was nothing to it. I can get a 3rd dirtbike up the middle when needed. We don't worry much about scratching dirtbikes.