The phrase "free advertising" means promotion or publicity for a product, service, or company that doesn't require payment. It's a way of getting people to know about something without spending money on advertising. Full definition
It's unfortunate because this site, like a library would be, was a great source of free advertising for Independent Authors (many of whom led the charge) including myself. (digitalmediamachine.com)
If someone offers free advertising on their style blog because they love your shop it's a compliment... not a scam! (suzannecarillo.com)