A little extra money can buy you a lot of five-star reviews in the world of online sales.

Fake reviews are easily sold in bulk by companies that promise to rocket vendors’ ratings to the top echelon of Amazon rankings, according to a report published by a UK consumer group.

Consumers’ Association, a UK-based charity that does research and advocacy, connected 10 sites that offered review manipulation services, including sales campaigns for sellers to boost their positive reviews, according to a report published on its Which website.

Researchers posing as an Amazon seller had no problem connecting with companies offering fake reviews in bulk. They connected with a German company called AMZ Tigers and, according to the story, were offered individual reviews for 15 euros, with prices reaching 9,000 euros for 1,000 reviews. An account manager “told us that AMZ Tigers could help sellers get an Amazon’s Choice endorsement in less than a fortnight by using its pool of buyers to generate sales on certain search terms,” the report said.

The Which article included a response from Amazon that noted it removes fake reviews and takes action against those involved in abuse. However, Amazon said it also needs “consistent enforcement and global coordination with stronger enforcement powers given to regulators against bad actors.”

The limited reliability of online consumer reviews was the subject of a recent Consumers Council of Canada research report. That report concluded that consumers rely on “gut feel” when assessing individual consumer reviews. The report noted that many online review sites contain numerous false reviews, created for numerous reasons: businesses seeking advantages, friends helping friends, employees supporting employers and consumers getting even.

The report concluded that online consumer reviews are instructive, but not representative sources of information, as comments tend to reflect polar experiences. “Consumers tend to write about extreme experiences (very good or very bad), but not unexceptional experiences.” The report concluded by counselling consumers to use reviews cautiously. “They can be a valuable resource, but consumers need well-developed critical skills to use them well. Relying on ‘gut feel’ to judge the authenticity of a consumer review doesn’t work.”