We try not to make price guesses without knowing the specifics, and even then, our guess is just that, a guess. It will bring what a buyer is willing to pay for it today. Tomorrow or next month, it may be more.
I can give you a reference for you to think about tho.
I sold my 1980 13 foot Burro in reasonably good condition with lots of cool mods and interior upgrades for 3200 on eBay. It needed some exterior paint
work and a couple windows
resealed, which would be typical for any trailer that is used and almost 30 years old. The buyer traveled from Seattle to get it.
He may have actually paid more if he was closer, it's a crud shoot.