In this Act, unless the context otherwise requires,.

(18) "purchase price" means the amount of valuable consideration paid or payable by a person for any purchase made including the amount of duties levied or leviable under the Central Excise Tariff Act, 1985 5 of 1986 or the Customs Act, 1962 52 of 1962 and 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 includes,

(a) in relation to -

(i) the transfer, otherwise than in pursuance of a contract of property in any goods,

(ii) the supply of goods by any unincorporated association or body of persons to a member thereof,

(iii) the supply by way of or as part of any service or in any other manner whatsoever, of goods, being food or any other article for human consumption or any drink (whether or not intoxicating), the amount of cash, deferred payment or other valuable consideration paid or payable therefor,

(b) in relation to the transfer of property in goods (whether as goods or in some other form) involved in the execution of a works contract, such amount as is arrived at by deducting from the amount of valuable consideration paid or payable by a person for the execution of such works contract, the amount representing labour charges for such execution,

(c) in relation to the delivery of goods on hire purchase or any system of payment by installments, the amount of valuable consideration payable by a person for such delivery;