A company sells products with spare parts and warranty , how can we account for the free spare parts provided by a vendor ?

If vendor give us these good free for customer we should not charge from customer and if free for company than first we should make a promotional account to enter these goods and than we can sale these goods as others.

you have to count first the remaining spare parts and then count the spare parts that sold after that you have to check the total amount of the spare parts that vendor gave make sure all the spare parts you counted from sold items to the items left will be tally in total.

Vendor giving free product to you. But your not giving free to your customer.

it should be take into account.

We can account this through proper  recording by using inventory stocard and proper labeling of the stocks in the stockroom, identify the beginning less the issuance or the usage.