Work of Advice, plan on cost to get the trailer registered in your state and if it must pass inspection, you will need to have it inspected. We purchased our and found out that it needed $400 of work to get it to pass inspection.
Old steel 2 horse trailers are pretty common and cheap, usually $500+. As an added bonus, they usually have a small tack compartment underneath the manger to store lead ropes, grain, trailer jacks or whatever.
Our 4-H leader uses one for his goats and can fit 6 large goats comfortably in it.
I have a 16foot stock trailer, but I also use it for horses, hay, lumber, cattle panels and all kinds of other things.
Yeah a bigger one would be nice so I could load the bed and trailer with hay. So far I've seen one decent two horse one for $2000 on craigslist. It's pretty good looking with tack compartments up front. Those tack compartments look handy but almost a waste of space for my purposes. This one has upper and lower doors up front for storage and it looks like the storage area takes up a 1/4 of the length.
We use a bumper pull 2 horse trailer. We got it at an auction used condition. The auction company said it was used once. I believe the smaller sized goat farmers just need a small 2 horse trailer. Most are almost completely enclosed to keep the goats out of the elements. These trailers (decent ones) can be had for as little as $500-$1000.
For 2000 you should be able to find a decent used stock trailer...15-16' keep an eye on craigslist and I use claz.org too. Be prepared to go see a trailer within 1-2 days and offer cash if u can. Especially if the price is right. We traveled 3 hours to get ours its a 16' 3 horse /stock Combo. Got it for only 900 so was well worth the travel time. It was in good condition too. So keep your eyes open and if you don't know about floors ect take someone with who can help you make a quick decision.
I have seen a 6 ft. lawn maint. trailer and a Tarter Gate Co. "Goat Tote" and a couple of ratchet straps make a great goat trailer in a pinch. I have seen a 10 ft dog run on a 10 ft lawn maint. trailer secured with a few ratchet straps make a goat trailer that will hold several goats and transport them safely. Goat people are wonderfully inventive and frugal using what they have and repurposing it to fit a need they have.