I helped operate a sporting goods store in central BC in the mid 60s.
I really don't think that IMR powder sold for 4.75 at that time. I think it was less. I started a lot of people reloading, so sold quite a lot of components and equipment. We sold more Norma than anything else, both factory loads and reloading components. All brands of powder was aout the same, and we sold Norma factory loads for exactly the same as Dominion Ammunition. Whille we were in the store factory ammo took quite a jump, with retail having to be 4.95 a box for standard 30-06 and similar class.
There's a good chance I have an old Norma can around that might have the price on it. I will later look.
I know at the store we got a 50 pound keg of H4831 war surplus, delicered to our store for $18. We doled it out in 5 pound bags and sold them for 2.50. a 5 pound bag.
I still have some of that bulk H4831 and it works perfect.