https://arstechnica.com/tech-policy/2021/02/fake-amazon-reviews-still-sold-in-bulk-it-costs-10900-for-1000-reviews/

Posing as an Amazon seller, a UK consumer group dug into the shady marketplace where fake reviews are sold in bulk by companies promising sellers a quick rise to the top of Amazon's charts.

"In December 2020, we signed up to 10 sites offering review manipulation services, including free or discounted products in exchange for reviews, or sales campaigns for sellers to boost their positive reviews," according to the report published yesterday on Which?, a website run by the Consumers' Association, a UK-based charity that does product research and advocacy on behalf of consumers. The consumer group said it found an army of "702,000 product reviewers across just five businesses" and "one site selling contact and social media details for Amazon reviewers."