I generally don't concern myself with the tax on items under 100k as it is aside from taking them into account when deciding which one is actually cheapest. It's just not worth the extra time to teleport all over to save a few gil when I could be crafting or flipping and making far more. You'd have to offer a pretty steep discount for it to be worth my time to go personally visit your retainer in some far flung corner of a random housing ward.