Last I checked, the griz 8" wheel was over $100, but the 10" is under. One is sold as an accessory and one is sold as a replacement part. I guess they get more for replacements. Neither has a bearing, so that's something to keep in mind.
A few people have gotten wheels from sunray, so you might look into them as well. Beamont charges $259, I don't know what Pop charges for an 8" bader wheel now since he stopped listing wheels on his site, trugrit charges $244, so you can bet it's that price or lower.