In this Act, unless there is anything repugnant in the subject or context,-

(y). "Turnover" in relation to any period means the aggregate of the amount of sale prices received and receivable by a dealer in respect of any sale or supply or distribution of goods made during that period, whether or not the whole or any portion of such turnover is liable to tax but after deducting the amount, if any, refunded by the dealer to a purchaser, in respect of any goods purchased and returned by the purchaser within six months from the date of such sale .