In general, discounts given by suppliers under normal trade practices, such as cash, quantity and trade discounts, are acceptable deductions and can be excluded for GST computation purposes unless:

1. The buyer and seller are related and the transaction price is affected due to the relationship;
2. The buyer undertakes certain activities for or on behalf of the seller as part of the payment under the contract of sale;
3. The buyer provides other goods/services to a third party for or on behalf of the seller as a condition of sale for the imported goods;
4. The price of the imported goods has received credits made in respect of earlier transactions.