I think that a consistent price generator should be used and I had idea for that :
- script can read map seed and of course chunk coordinate this would be used to indicate the seed for generating chunk price
- after mod or blacklist change, script can index a list of usable items,
- the price of each chunk is generated with a seed based on the position and map seed,
- prices don't need to be saved, but if it does it's only a cache that get invalidated where mods or blacklist or modified
