Frankly, I care least if they received product for free. What do they actually write in the review, is more important. Are they building a castle in the air or really talking about the product itself? Those who spent hard earned cash, their reviews are sometimes like 'awesome product, 5 stars', what does that tell us?
I learnt to ignore such footnotes and decided to read the reviews to better learn about the product. I don't mind asking question about the product, then you know who has actually used the product. Go back and read their reviews. I have found so many reviews where they got product free have lot more substance to it then those who spent hard earned cash. Plus, my observation is, not everyone that received a free product is on 5-star bandwagon. There are so many 1-star reviews and a free product was received. The point I am getting at is, if you spend some time in actually reading the reviews, you would quickly realize who is faking it. The extensions like Fakespot aren't as good as actually reading the reviews.
Since you talk of salt and pepper grinder, I was in same situation a few months ago. I got, https://www.amazon.com/gp/product/B00PID7KAM/
Almost all detailed reviews got the product for free (or for discount, whatever). But when I actually read the reviews, I found them trustworthy. I got this one. Have been using it for few months now, no complaints.
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