It wouldn't surprise me to find out this is some kind of "business" - where you have an Amazon seller account post up various items charging only pennies, then you hire a bunch of people to purchase the products (so they are a "verified purchaser") then review them with high ratings (and maybe a few lower ratings just to make things look good).
Then somehow sell those SKU codes for the items onward where the item information (description, photo, title, etc) are swapped out - so now you have an instant "best seller".
This can also of course be done by an individual seller - they just get a good product, sell it, get some great ratings on it, then change out the information for another product but keep the SKU the same. Works best if the products are very similar (I've seen this too - where the reviews, if reading them carefully, seem to refer to say a USB thumbdrive, but what is being sold is an actual hard drive, or memory, or sdcard, etc).
The other way, of course, is to sell multiple products with different "colors" (but each is actually a different product). Then you have reviews all over the map, all for the same SKU - or at least in the same general comment mix for the product being sold. So now you don't know if the comment is referring to the product you want, or some variant of it...
All of that said, I can kinda understand why this is possible, even desirable - for Amazon to give that kind of control to the sellers. They could try to police it, but how do they police and enforce SKU usage and such, without also busting legitimate uses? That's probably the difficulty.
There's a similar problem with some sellers posting items up with insanely large prices (like a pack of gum for $10,000); from what I understand, this is done to prevent an item from being purchased when it is out of stock, or to keep the reviews (maybe in conjunction with SKU swapping?), or a few other reasons, with the idea that nobody will buy that product with such a strange high price on it (plus sorting moves it to the bottom usually). Unfortunately, this also screws up when you want to sort high to low prices, to find a possible "better product" that is priced higher because it is made differently and better than "regular ole' generics" (I faced this recently while looking for a shielded audio cable).
Here again, though, policing it would be nearly impossible - how is Amazon to determine that a particular package of gum isn't worth $10,000? For that matter, maybe there's a buyer out there looking for an elusive pack of gum and is willing to pay the higher price? Seems incredible, but I am certain there's at least one person out there ready and able to do so.