Dvat clarification

if company purchase raw material and also take input of the same and manufacture the item and sells their product, out of the total finsihed product 30% goods they provide as sample or free gift and on such goods they not impose output vat on both these transaction. 

Whether sales  tax liability occurs on this transaction?

Alternatively, they may reverse input vat accordingly from which they takes from their purchase.

Kindly provide answere of above queries?