Is it "too expensive" to take a .07 billion dollar vote before imposing an annual tax costing 164 times that number?

Tony Abbott has argued a $70m plebiscite on the carbon tax will give Australians their say | The Australian

Greens Leader Bob Brown said his party would not support the "extremely expensive" political move
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"It wouldn't be cheap, but let's not forget that this is an $11.5 billion a year tax that the prime minister wants to impose on people, a tax that she wasn't honest about before the last election."