LGS prices may be higher, but I don't think much of the difference is because of the HAZMAT fee. You can ship up to 48 pounds of HAZMAT on one fee, so that works out to about fifty-eight cents per brick of primers or pound of powder. Even adding a "profit margin" to the HAZMAT fee doesn't account for most of the cost difference at the LGS, at least not my local shops.
I just got an order in that weighed 57 pounds and contained 4 8# jugs and one sleeve of 5000 209 primers. We couldn't get the second sleeve because the weight would have been over the max of 70#
How do you get $.58/brick of primers?