For the purposes of this Subsection, the following definitions shall apply:
(1) "selling price" means everything which constitutes the consideration obtained or to be obtained by the taxable dealer from the customer or from a third party, including subsidies directly linked to the transaction, taxes, duties, levies and charges and incidental expenses such as commission, packaging, transport and insurance costs charged by the taxable dealer to the customer, but excluding the amounts referred to in Article 79;
(2) "purchase price" means everything which constitutes the consideration, for the purposes of point (1), obtained or to be obtained from the taxable dealer by his supplier.