I'd buy the wheels I posted and find tires off eBay. I think you should be able to get tires for $50 ea. (shipped) last I looked. Parts pricing is usually all over the board depending on where you go. In many cases, you're arguably better off picking up a complete (or mostly complete) tractor for parts in the long run, IF you can find one. Otherwise, I can't really blame dealers for the prices they charge as they are essentially storing parts, in some cases for years, for someone to maybe buy them some day and usually they don't get the parts for free to start with. Plus there is a fair amount of time and effort involved with the transaction especially if they have to take things apart to get to what you want. Also, check out parts for a newer Kubota, John Deere, etc. and you'll be amazed. It is usually a financially humbling experience. By the way, last time I priced a used front axle for your machine I found one for $1200 from a dealer. So spending $300 to get the correct wheels/tires may be a worthwhile investment now to minimize its failure in the future.