As they go on about in the thread, but can't show because it's against the rules of the subreddit, it's common 3rd parties to sell for a lower price than Prime, but then make it back up in shipping.
Read the page carefully. There's often an "Available for $, but without Prime Shipping" or "other resellers" link that may be cheaper. Prime is just about getting free or quick shipping, it's not a guarantee of the lowest price.
Add Redcard credit or debit and you get a $40 coupon plus 5% off instantly once approved. That brought my $150 sale item down to $107. Original price was $200. Even Prime can’t beat that! Also Target trolling Amazon with lower taxes duplicating items AND price matching lol