Does anyone know how to become a cosmetic sales rep who works as a vendor in department stores?

I have been working in cosmetic sales for years and know that there is a difference in pay between people who work for the department stores and those who work directly for the company. I cannot ever get info. from these people on how to become a ';vendor'; does anyone have any information?Does anyone know how to become a cosmetic sales rep who works as a vendor in department stores?
I know that Dillard's and Macy's start you off at $15-$18/hr but they require past experience. I was told by my friend a former Macy's HR manager that the department stores pay more because Macy's will pay you $8.00/hr and Lancome or whoever you would work for would pay you $8.00/hr so your salary ends up being $16.00/hr plus 10%commission. If you were to work for Sephora then you will only make like $8-$10.00/hr because it's a independent company.