Cost Method To Value inventory

So I used the Cost Method to value End of Year inventory, which turbo tax states that it is common to use the amounts I actually paid for the good at wholesale. For example, if I were to pay for 10 stuffies at $10 each ($100 Total) for 2022 and only sold 5 of them, I will report End of Year Inventory Value of $50 for the 5 that I did not sell. 

 

My question is, what if I acquired 100 books for free from Facebook and sold 50 of them in 2022 at varying prices. I'm left with 50 books. In order to be consistent with how I reported the first example as I also did last year (Cost Method), do I report $0 since they were free to me?