Most manufacturers don't charge customers shipping fees on free grocery samples, though the specific details of each offer vary by promotion. Customers need to read the fine print on each offer to understand any hidden charges or obligations.
Most companies factor in the price of the product and shipping into the marketing costs for promoting a new product, and thus don't pass the charge onto consumers. To keep costs low, however, many manufacturers require customers to sign up for special accounts to access the samples or place a limit on the number issued for each sample. Some promotions require consumers to claim the sample online within a given time period to receive it, controlling how many samples the company issues.