I posted about this on HN recently[1]. Within the last month, I've been getting an increasing amount of native ads on different platforms for "Free [Product]!". If you engage the ad, you find out that the ad-purchaser wants you to buy the advertised product and leave a positive review for it on Amazon, after which they'll refund you for the cost of the product.
Some of these items have thousands of positive reviews[1], which is misleading to consumers who rely on honest reviews to guide their purchasing behavior. Also, it is almost comical how difficult it is to reach out to Amazon about this issue as a user.
In the end, I just contacted my state Attorney General's Consumer Protection division and the FTC.