Hi Helen, if you were invoiced for the goods or payment was received on or after 1 July 2018, GST will be applicable. If goods were ordered before 1 July 2018, the existing GST rules apply even if the products do not arrive in Australia until after 1 July 2018. Start buying, Helen! @stampingpaws wrote:. Hello All, Remember you pay tax on income LESS COSTS so if you sell $20,000 dollars worth on EBay and it costs you $15,000 to purchase your stock you will pay tax on the $5000 profit LESS any expenses associated with your selling activity eg EBay and Paypal fees, postage, packaging materials, office supplies, internet subscription, cost of your accountant's fees.