Taxable Goods + Gift(Taxable)

Karthi (Tax Consultant) (70 Points)

02 February 2019  
Dear Experts Pls advice,
I make plan to sell products easily as, I purchase refrigerator & home theatre from a registered supplier.. If customer buys refrigerator, then he eligible to get gift as free of cost.. But I compensate home theatre cost + profit into refrigerator..
How would I raise sale invoices to file return?
How do I setoff in books?