After reading many threads, and ofcourse personal experience.. I have come to the conclusion 90% of the pbase has no idea how the markets actually work with regards to the difference in what city-state the item is being sold in.

The main thing here I would like to point out is extremely simple, obviously not well known, and would stop the trend of undercutting by 1 gil or another trivial amount.

Here is how this works... PlayerA is selling an item in gridania for 10k.. PlayerB is selling the same item in Limsa for 9,999 gil.. PlayerC is wanting to purchase said item and is currently in gridania. Now.. if PlayerC buys the item from PlayerB, they actually end up paying 10,494 gil due to the 5% tax (currently set at 5% across the board for me)... but.. if PlayerC buys the item from PlayerA, since the item is in gridania and there is no tax(delivery) charge.. then that item will cost exactly 10k.

PLEASE LEARN THIS PEOPLE!!!