Here the way I look at things.
Air freight 100 pounds of Figi rock, you get 85 to 90 pounds the 2 boxes are about 6 pounds each. The pickup at the airport cost gas money say 10 dollars, air freight is about 70 dollars, gas money is about ten dollar for pickup and things from the pet shop. The salt for curing rock costs, the tank costs, powerhead cost, lighting cost, heater cost, and misc costs all add up. Even if you have some of this stuff it is about .80 cents a pound.
The smell alone of curing rock is bad.
Note if you decide to buy rock by the case remember the stuff in the bottom of the box, the tiny rubble, is worth the most so don't toss it. This is what a case of rock has that I don't.