"Gift" is the word used in the rec regulations so trading/bartering would not be considered legal, officially. In the real world it'll work no different than that and how the BM works, gift up to 30g and charge $$$ for the baggie, seems legal enough to me. Cuttings can be "gifted" with no roots as they are not considered plants, rooted plants are not allowed... officially.
The trick to all of this gifting or sharing is to keep it low and quiet, not like they'll have the knowledge, budget, or resources to actually monitor any of it. The only people that I've seen reported as charged so far seemed to put themselves in situations where they were magnets for cops. If you don't want to get attacked/bitten, don't dangle a steak in front of a hungry dog...
