Probably on the order of the Missal pricing. Some cheaper than others based on the paper used the cover and binding.
The triple combination leather bound with thin paper, is going to cost.
The Book of Mormon paperback printed by the tens of thousands in multiple languages, free in the sense that nothing is free other than perhaps salvation, as a free gift, and we all should know the cost of that gift to mankind.
Generally the D & C and the Pearl of Great Price are not free.
Pity; since most LDS practices come from the D&C's and not the BoM.