I did nothing concerning sales.
I was told that it was a paid internship but did not receive any compensation. When asked he told me if I did good work that we would revisit it later, but that never happened.
When I applied the flyer said that there was a possible 3 month extension of the internship, but when I approached him about it, he said that I would need to stay for another 6 months to secure a full time job.