Buying cosmetics online from a representative, like Avon, is a pretty good deal for the consultant. He or she gets the sale and the customer has the merchandise delivered to his or her home through the mail. The consultant doesn't have to deliver it, which is a major advantage for said consultant.
In my opinion, Avon products are probably the easiest to sell. The commission might not be as large, but because most Avon products are pretty reasonably priced, they're an easier sell, for sure. It's a lot easier to promote a $6 tube of lipstick over a $30 tube.