It's much more than that. In fact, this new $10,000 credit, which would replace other credits, would be very costly—$14 billion—because many low-income families would benefit from it. It's necessary, because we can't just cut taxes for the wealthiest without doing something for the less fortunate. However, there is a fairly significant cost.
As for the GST, we have calculated that this would require an increase of 2.8 percentage points. Another possible option is a 3.2% payroll tax, which could be more proportional, because we could exempt, for example, the first $15,000 earned. So, there is a certain degree of proportionality, and it applies more broadly, even to the wealthiest. So there are two options.