I really hate selling things to NPCs and buying from NPCs- they buy my hard farmed items at 300 gil and then try and sell me a level 20 helmet for 200,000.

Is there some way to build in a Consumer Price Index for NPCs to regulate this? It would be relatively simple, take one or two of the best selling items from each market ward and build a price index relative to the sever which would have NPC vendors participating in the market. I think this would help regulate inflation of gil as the game progresses as well.

Example:

Say a vender sell steel gauntlets for 10,00 Gil and steel chain mail for 50,000. It could look at the average selling price and say the market has seen the price for the armorfitters row margin increase 15%, the vendor would sell them for 11,500 and 57,500. The CPI would also effect the selling price to vendors, meaning the sell value to NPCs would increase by a 15% margin as well.

The NPCs don't have to be competitive with prices (obviously it's better if most transactions take place on the player side) but it could add more flexibility to NPC goods and the option of selling to NPCs as well.

Seeing as to how it's a market specific measure, if mining goods are selling low and alchemy is high then the NPCs would have cheaper ores and etc while having more expensive prices for alchemic items. The prices could be updated every 24 hr earth time, and since it's a ratio + or - doesn't seem too complicated.

It's just something I've wondered why MMO's don't implement in order to help regulate the amount of gil going in and out of the game.