Fascinatingly, for most of Pre-(H)istory it seems they had something called "taxes". This was a system where you would give a percentage of almost everything you owned to whatever group was most powerful at the time. Buying, selling, or even just holding, you were supposed to calculate and then pay for a part of that.

This led to a lot of resentment, and would often continue to increase year over year!

Although our system has its flaws, the total ownership by the Walled Cities of all land within the walls, and the leasing out of it, allows for a very simple one tier system. Of course a person is free to buy or sell within the walls without paying any additional fees. 

We do however have that pesky "repair bill" that must be paid out by all citizens whenever a significantly strong monster attack occurs...

-Notations on culture, by (H)istorian Costanza Godhand