Can't buy the $20 '04 driven sprocket for WR450?

[MorrisWR]

Well, I tried to order the 2004 WR450 rear 52 sprocket which were about $19-$20 online. I got a call from Ronnies saying they no longer are able to get that sprocket because Yamaha updated and now it's $65! Better quality.

I'm sure it is better but that's a huge difference. I think I'll just go to aftermarket for that price (or just change the cs which is much cheaper). Heck, I could buy a chain almost for that price.