You can track giveaways or samples so that the Cost of Goods Sold (COGS) account, Inventory Asset accounts, Quantity on Hand, and the Average Cost are accurate.
Intuit recommends 2 solutions for this problem. Choose the one that works for you.
Use the method appropriate for your report basis.
Use a zero dollar sales transaction. Changing the rate for the item to zero affects the sales price only. Amounts posted to COGS and the Inventory Asset account remain the same as normal.
Use a sales transaction discounted at 100%.
This transaction credits the Inventory asset account and debits COGS by the same amount. It does not affect the accounts receivable or bank accounts.
You may also wish to enter the sale of free samples or giveaways as an inventory adjustment. This is a better option if you want to record the sales at the end of each month. One advantage is that you can post to an expense account for this kind of sale, without also posting to an income account.