MLMs have to be up there with the biggest scams, ever. My mother was scammed over and over under the guise of friendship. As a kid I remember there was very little money but there was always enough to buy another order of whatever. The ugliest part is that once you become a member you fall into the trap, you become part of the scam and become a scammer too. It's ultimately very sad once you learn it's a legal pyramid that eventually collapses and you're left holding the bag. And your "friends" led you to it.
I was approached by people trying to get me into a pyramid scheme at least thrice in my life.
One was a friend who got into it in high school and said I could get in on it too for 100 USD (~2004). Another was a random stranger I struck up a conversation with at a bookstore in around 2011. The last was an old boss, who attributes his drastic weight loss to a strange drug that he's peddling and says I can get in on.
It's crazy. I was 17, 24 and 37 and all 3 times I knew there was something super suspicious about these and never engaged.