Here’s the screenshot that I sent to Avast. There is nothing itemised near the second circled figure to indicate that the AU$8 disparity is attributable to tax.

The point that you are not getting, Eddy, is that Australian consumer law REQUIRES merchants to include the GST as part of an advertised or quoted price (unless the merchant takes the unusual option of specifically stating that the price does not include an expected GST obligation). Avast ADVERTISED (and repeatedly) what I was going to buy at AU$79.99 without qualification – which under Australian law implies that GST has been included in the cited price. If a merchant advertised something at a certain price on TV, and then sprung a GST tax “surprise” on customers when they came to actually purchase the product, that merchant could be prosecuted.

It may be the case that in other places – say, in some states of the US – sales tax is not included in the displayed price, but is added at the checkout of the store. That practice will not fly in Australia. Because merchants in Australia are REQUIRED to include the GST as part of the cited price – and because every other merchant here seems to be able to abide by that requirement – Australians are legally entitled to assume that a price cited without any immediate qualification about tax is already inclusive of any GST imposition – no ifs or buts or resorts to the fine print.

It’s a legal requirement in doing business in Australia. If Avast are acknowledging an obligation to collect GST for the Australian government, then Avast are implicitly acknowledging that they are operating under Australian law in marketing their products here. Therefore, Avast also need to ensure that their advertising and quotation of prices conform with Australian law.