If I'm not mistaken, U can get one at electronics shop. Not the one selling audio equipment, but those selling elec. components like resistor, capacitor, rechargable battery etc. Get the one with battery charge indicator.
I usually go Ban Hooi @ Jalan Kapar, but a bit far, and I'm a bit lazy. 3 out of 5 times will do on-wheel balancing, for some reason my stupid car always off balance (FWD).