Hi Stephanie and welcome to the world of FGRV's.
Gotta say though, that with your budget and requirements it's going to be a tough order to fill unless you are prepared to do more than a small amount of work.
16' Scamps in decent shape are occasionally seen in your price range, but that wouldn't leave much for usually necessary repairs on an older FGRV.
You might try following the ads on molded fiberglass RV's for sale
Molded Fiberglass Travel Trailers For Sale | Fiberglass RV's For Sale
but be ready to pounce if you see one withing your budget, especially until well after summer is over and prices start to drop for winter.
In this venue, fair priced FGRV's tend to last only a few days after they are posted and underpriced ones will sometimes last only hours after posting.
That said, scammers abound with low prices. I suggest that you read up all you can about our trailers and ask lots of questions before you go looking.
If possible try to attend an FGRV rally
or at least look at a few you can't afford ASAP.