I agree with Matriox here, it should only be used for late game. With that being said, the price is theoretically reasonable. However, I think the tower is pretty weak considering the reputation it has and for the price it is, it should deal a bit more damage to balance things out.
In my opinion leach Tower is an extremely wasteful use of money early game, the only time you should place leach is if ur going late game. Leach tower should not be your number one thing to do as you start the game you should be thinking about using that money for rushing / exp