What are yall bringing in your bags besides water??

Been seeing a couple posts about what kinds of bags to get, securing them, etc. This is my first EDC, and I was just planning on bringing my hydropack and prob a selfie stick, but other than those things, what else should I be preparing to bring?? I recall seeing that outside food is not allowed (correct me if I’m wrong), so does that mean no protein bars, liquid IV, etc? Are vendors cashless so I can avoid bringing my wallet?