If you are just taking a piss, why do you need so much water?
furthermore if you are paying you own bill, I dont see any reason
why you wont want to save on water consumption.
or maybe you dont flush your toilet after you piss huh? 
I am not sure about the cost, but all i can say is that it is just
a mechanical device and I shouldnt cost alot if our government
would to make them or buy them in huge quantity.