I always start with Messicks.com and see what they have first, OEM parts. From there you can check the big boxes like TSC if you want for replacement. Of course, It's always worth the time to take a look at what's available on Ebay. You need to decide if you want to plain or fancy, OEM or not, and of course, consider or rule out the expensive choice of suspension. There are people that rebuild seats, and some do a beautiful job, but it only make sense if you can find one and your seat pan isn't shot. You would likely have better luck finding someone to rebuild if you are in a boating area. Lots of boat seats need to be reupholstered and some of them are very similar to tractor seats. Good luck. My seat is 11 years old now, outdoors most of the time and for the time being I went with duct tape and a seat cover. I'm now on my second cover, so a replacement is not too far down the road.