Unless you are engaged in the trade or business of selling products, the items you sold are capital assets and you have capital gain. Otherwise, the items are inventory and their cost factors in to the COGS.
If the items are capital assets in your hands (which is likely) and you were the donee (i.e., the person who received the items as gifts), then your basis is the donor's basis (the basis of the person(s) who gave you the items).
Regardless, you need to know the basis in your hands in order to calculate a profit or capital gain. If that cannot be determined, you have to use a basis of $0.
