I replaced mine with rather inexpensive new wheels from a local marine trailer retailer. I think they were $35 each, and there were at least two or three options (galvanized, painted, 'spoked'), in the 4 on 4 - 13 inch style. Later, when tooling through Northern Tools, I saw I could have gotten replacements even cheaper there - $28 I think.
My trailer had three different wheels when I bought it, and none of the tires
were the same make and vintage. For just a little over $200 I was able to put matching new set-ups on both hubs and the spare. Might be more than you were hoping to spend, but, along with new bearings, the peace of mind it gives me on the highway is worth it.