I'm still here! I don't post much, but I lurk in the background.
I think I paid $600 for mine and I recently sold it for $1000. That was with new tires
and hubcaps, new paint
, new floor, new interior LED lights
, and new LED running and brake lights
. It really depends on your market. I live in western Washington State why dry and lockable utility trailers can fetch a premium.
Given what new enclosed and lockable trailers sell for, I think a price in the $600-$1500 range is fair depending on the condition of your trailer and your market.