A couple tried to recruit my husband and I into Amway when we were newlyweds. Even though we had very little money, after the presentation we told the couple that we had enough for our needs, and were really happy, so no thanks. Just the fact that we weren't interested seemed to cause tension in the relationship. They had never had us over before or after, so we felt like we were just being used anyway.
Another couple we knew was into Amway, and the thing that creeped us out was they always called it "the business", and never said to anyone in our group of friends exactly what it was, at least at first! Seemed like a red flag, but we didn't know much about it at the time.