You might try CycleGear if there are any in your area. Not the brightest nuts in the drawer, working there, though. I ended up pricing mine out at a different store, and getting sizing done there. It would have been a couple dollars less at cycle gear, but they weren't that confidence inspiring in thier ability to guide in getting a correct fit.
This being said, if you know what size you need, or can figure it out well enough on your own, they were lower than any other store in the area, and had a decent selection of Arai helmets, as well as replacement visors.