It's a club you have to pay to be in. It's no different than Sam's Club or Costco, but this one is online.
It's different b/c non club members can buy most the same products. I didn't say it's illegal. I said I do question the legality though.
I'm not sure what you are trying to say. The same stuff you would pay one price for at Walmart, people who pay for a membership can get cheaper at Sam's Club. On amazon there is a price for normal customers, and then there is a price for people who pay for the Amazon membership. Amazon Prime members also get better deals on shipping... and great deals on lots of stuff on Amazon Prime Day. I've been a College Student Prime member for like 3 years. When you are a student you can sign up and you get the first 6 months (?). for free. If you plan on spending much on Amazon it is worth it. Plus you get access to music, movies, original content, and sometimes free eBooks, and so forth.