Whether entry tax on free of cost goods is payable or not

I have a client, which made a contract with his Supplier for delivery of certain goods. Contract says that Out of 100 Goods, supplier will sell 5 goods Free of Cost. Now, Supplier Raised the Sale bill amounting to Rs 59 Lacs (only for Excise Duty Purposes). They have not charged any CST on the same since value is nil. It is also written there that Basic Value Free of Cost. I would like to know that whether Entry Tax is payable on the same or not. If payable then on what amount?