It appears to be a nice trailer based on these photos - but that doesn't mean there aren't issues that aren't visible that could effect it's value. Does it have a clear title? You say you "ended up" with the trailer, so do you have the title and legal ownership of it that you would need to enable you to sell it?
It should be fairly easy to look around at trailers listed for sale in your area and find some of similar quality/condition to give you an idea of the going rate for your locale.
I've had this trailer since 1998, or I should say "we" - until the divorce, so that's why I said I ended up with it. I've got around 1000 in it since the paint & new tires. I do have a clear title, I 've looked on graigslist but most everything I see that age is really beat up and rusted (this one has been taken good care of). Well, thanks for all your suggestions, I appreciate all the post.
Around here I think that trailer would bring close to 3 bills....we looked at a bunch before we bought ours and $1000 gets one ready for the scrapper.
If you don't need to move it real quick then price it up a little and see if you get any offers. You can always come down if you need to. Most people are going to expect you to come down some...so take that into consideration.