Display local tax at step 1 of checkout

[alanna]

When purchasing a product tier item in an OCNZ hosted Collective, GST is applied. However, it is not displayed on step one and only appears on step three. This is misleading as it first shows the payment amount of $30 when it will really be $34.50.

[Betree]

Taxes are surfaced on step 3 because, for VAT, they depend on the contributing profile (whether it's an individual or an organization, where it's located, etc). We could do a simple exception for GST and guess the amount a bit earlier since it does not have such dependencies.

[alanna]

Maybe on step 1 it should just say the amount "+GST" or "+VAT" so it's clear that will be added later?