Where to find good price for BFGs?

[guruerror]

I'm thinking about going from BFG MT 37x12.5x17s to 37x12.5x20s and was SURPRISED by the price difference in the two tires.

I can find the 17" version for under $400 but can't find the 20" for under $600...anywhere. Logic would indicate that LESS rubber is needed to make the 20" then the 17" so I find it odd that the 20" version is so much more expensive.

Does anyone have a good site for good prices on BFGs? If I can't get a good price I guess I'll stay with 17" rims.