The reason that you pay taxes on money is because, all fiat currency (thus why it's called fiat currency, as opposed to money) is simply the principal of a loan taken out by the government, in the form of bonds, from the Reserve Bank (privately owned, and not accountable to governments) for the privilege of printing and managing their fiat currency system).
Thus the Reserve Bank creates currency, by adding a 1 and lots of 0's on their computer, then loans that amount to the government, which they then put into circulation, as legal currency.
We, the people, are the collateral for that loan.
That's why you pay taxes :)
Peace.