A common characteristic is that you are required to purchase something before you are able to start work. You are not told that you will have to sell these items yourself or that there is usually little or no market for the product. Of course, these promoters will find some reason to reject everything you send them. Some of the people you may meet are scam artists looking for easy marks. Prisoners' personal ads have proliferated in recent years.
Many ads placed by prisoners are part of a sophisticated mail fraud scheme.
They slowly gain your trust and confidence. Eventually, they will ask you to cash one or more money orders. They may say it is for legal expenses but they can't cash the money order at the prison and the attorney will only accept cash. They ask the mark to cash the money order and send the cash to an accomplice who may be represented as their attorney. All companies that sell money orders, routinely compare cashed ones with the original receipts.