According to the Federal Trade Commission, envelope-stuffing schemes are not legitimate businesses. These scams follow a pyramid scheme model that is unsustainable and prevents most participants from earning much, if any, money.
People interested in working from home can use the Better Business Bureau website to see whether certain business are legitimate or have received complaints from participants.
Envelope-stuffing schemes typically require participants to pay a fee to sign up. The letters they send out are advertisements for the scheme, meant to lure in more participants so that the company can earn more sign-up fees. Participants usually earn a small commission based on how many people they successfully sign up, but after a span of time there are so many participants that most of them earn nothing.