My spare is an old Ford Ranger rim - if it's not an exact match to my Prestige wheels, I don't know what the difference is. Try a junkyard for a wheel - you'll find good wheels and get them cheap, and there's a chance you can find someone here on the forum who's buying new tires for their trailer and can get you one to mount on the wheel.
My complete setup came from almost exactly that! Picked it up at a rally and knock on wood - have never needed it!
Crownline Airlines 2001 202BR with WakeAir tower