(xlii) "Purchase price" means the amount of valuable consideration paid or payable by a person for any purchase made including any sum charged for anything done by the seller in respect of the goods at the time of or before delivery thereof, other than the cost of insurance for transit or of installation, when such cost is separately charged, and shall not include tax paid or payable under this Act, by a person in respect of such purchase.

Explanation I - The amount of duties levied or leviable on the goods under the Central Excise Act, 1944 (I of 1944), or the Customs Act, 1962 (52 of 1962) or the Bombay Prohibition Act, 1949 (Bom. XXV of 1949) shall be deemed to be part of the purchase price of such goods, whether such duties are paid or payable by or on behalf of the seller or the purchaser or any other person.

Explanation II - 'Purchase price' shall include any amount payable by a dealer who purchases goods for anything done by the seller in respect of the goods at the time of or before delivery thereof to the buyer.

Explanation III - 'purchase price' shall not include-

(a) the cash discount allowed by the seller according to ordinary trade practice, if shown separately;

(b) the cost of transport of the goods from the seller to the buyer, provided such cost is separately charged to the buyer;