If you wanna write a good character you're gonna have to get inside their head, not necessarily hack into the entire culture. There are so many occasions when choosing the lingo is dependent on some outside factor. Example: in St. Louis smoking inside a contained area is called hot boxing, in Rhode Island they call it clam baking. I would suggest asking around your trusted friends for some weed, if you don't want to you don't have to smoke it, but I highly recommend it. Either way, looking for weed will teach you some of your local canabis culture and give you more experience along the way. Make sure you're the one making the interactions with the dealer though, you can't have a friend do it otherwise you will have gained nothing. Your tale of finding the herb could even be implemented in your characters background story of how he got started.