My old assistant manager used to sell ketamine, pills and bud at a pizza place I work at before he got caught and fired. This is how it went.
Client walks into pizza joint.
Hands him money for droogs.
He hands client an empty pizza box with said droogs inside.
"thank you, come again"
Mind you, he managed to keep this up for about 6 months, and cleared like 7 grand before the owner caught on.