Well I've never paid more than $2,500 for a horse, but I sure as heck wouldn't pay that little for a trailer! Around here, a SAFE trailer is at least $5,000, and even then, it'd have things wrong with it. Rust, chipped or flakey paint... A new horse trailer is in excess of $10,000 and a nice one easily in excess of $20,000 - this is JUST the basics. Horse bays, tack trunks, nothing more. With living quarters? Forget it if you don't want to pay $25,000+. And that doesn't count a kitchen, which will be extra, and water supply, extra again. Most people just camp in tents, or sweep out the horse bays and sleep in there. Or in the car if they're determined not to get dirty/cold.
In saying that, I don't actually have a trailer. Probably because I refuse to buy the unsafe wrecks that actually ARE within my budget.