Housing permits?

[Lexia]

I believe a npc in each Residential Area sells it (the Estate Caretaker from what I remember), and it's an item that allows you to purchase a section of land (called a lot) for a house in a Residential Area. Unfortunately land is a limited resource and vacant lots have since all sold out on most servers (and especially so on Balmung).

This is not how it works, you don't need a permit to buy land. You can buy any lot that available if you have the gil to do it. The permit builds the house on the lot that you buy, otherwise you just buying a empty piece of land.