How to prevent customers from buying a product that should only be available as a Free Gift?

How to prevent customers from buying a product that should only be available as a Free Gift?

The Free Gift extension allows adding promo items that are not visible in catalog. If you don't want your customers to purchase the items meant to be Free Gifts only, please set the Not Visible Individually option on the configuration page of your free gift item (Catalog → Products → Edit the product → Visibility). 



This way, the product will only be available as a Promo Item and will be unclickable on the shopping cart page.