Taxing your citizens

I have been having a little trouble with a new war like map i have been creating. What i want to do is be able to use an autocast ability on a basic house that adds gold everytime it is used. The idea is you can build commercial buildings by it, and the mana will regenerate, simulating the people in the home recieving their pay. My problem? How can i get an autocast ability that will give the owner,lets say five gold every 10 seconds?

Base a spell off that one mana regenerate spell the statue thing for undead has...

Events-
A unit casts a spell
Conditions-
Ability being cast equal to <your spell here>
Actions-
Set gold of player to gold of player + (however much you want taxes to be)

How would i make it give money though?

u mean convert mana into money? well um that would mean you would have to cast the spell for 1 mana and then what the guy above you posted will work, though it could be a little laggy. there isn't a way to check for mana used so sry.

well, maybe i could use triggers, saying every time that i tax, it would take one mana from the building...and nearby commercial would give mana. How would i take mana and give me money for a trigger though?
(PS i cant download maps off of a thread, comp trouble u know)

maybe you could have separate abilities and each one would give a diff amount of gold; you could set a differnt ability foir a higher tax rate.

But what would i base the ability on, there is no autocast that gives you gold every so often...