i do not know how price are calculated but somewhere, you have a constant that dictate price of ore ( i think )
the thing is to detect if there are new ore in the mod that are added, if this is the case, its easy to think that one modifier per mod could easily disable purchase for some mods. you will have to add a compatibility patch anyway for each mod that add ore ( i think)
once this code is written, is almost copy/paste to add a new option under the new one for a multiplier for another mod
Again, this take time, that maybe you do not have or do not want to spend on this mod. like i said elsewhere, black market 2 was not updated, i think you will have a great sucess with this mod