Plug

A plug is one's supplier or source of certain goods. It is most commonly used to refer to drug dealers but can also be used for suppliers of other items as well such as clothing, shoes and accessories.

Stoner1: Ah shit, my plug just got locked up last night by the feds.
Stoner2: It's good, I'll hook you up with mine.

Hypebeast: Would you cop these or drop?
Averageguy: You can't even get those.
Hypebeast: I got a plug.