Folks are heading online to do a lot of their shopping on Black Friday, and with Cyber Monday coming up, it'll be more of the same.

Companies now solicit reviews for their products to get a high ranking before these high-traffic days.

But, they may be trying to trick you into buying their products.

By now we know you can't trust all reviews for products on Amazon. Even Amazon knows that.

The way these sellers are getting fake reviews is evolving making them harder to spot. Rather than buying fake reviews that often sound fake, they're taking to Facebook. Simply search for "amazon reviews" and you'll find dozens of Private Facebook groups where sellers and shoppers connect to make deals.

Here's how they're doing it: A seller posts a product looking for reviews. I found a seller offering this tablet for free in exchange for a review. The seller doesn't send a link, they show the name of the product and the image in an attempt to trick Amazon's algorithm that spots fake reviews.

The reviewer searches Amazon for a drawing tablet. When they locate the product, they purchase it under their name. Get it shipped to their home. So, they get the "verified purchase" label, which generally has more influence on shoppers. Once they write the review, the seller refunds the purchase price to the reviewer. Some also pay the reviewer. The $70 tablet has 4 and a half stars and 159 ratings.

The problem with this tactic is that once reviews are posted, the product appears near the top of Amazon searches, but usually only lasts a short time.

This study by researchers at UCLA said soliciting fake reviews on Facebook leads to a "significant increase in average rating and sales rank, but the effect disappears after roughly one month."

To protect yourself, search for reviews of the products somewhere else online, and don't trust that every review you see on Amazon is honest.