There are three different kinds of meds as far as the dispensaries are concerned. As Mr. Murray mentions above, the bottom of the list is material that will test as contaminated with either mold or pesticides. If you can't get that right, don't bother applying - retail establishments won't do that deal.
That leaves two grades, the stuff they can live without and the stuff they can't live without. The vast, vast majority falls in the live without category and the dispensaries are flooded with that stuff, day in and day out. The good owners lament the steady foot traffic of pathetic growers showing up with sub-standard material and fear earth-bounding fragile ego's with business model pricing schedules. "Postal" can describe many reactions from closeted growers who have no idea of standards and value.
The more nefarious dispensaries use the situation to low-ball growers, and in fact that seems to be the standard of business at this level. They see so much traffic it is almost a game where they throw ridiculously low numbers out on a dare, seeing who is desperate enough to accept any pittance whatsoever. It sucks, no one goes home with a soul - but thats life in the fast lane!
There are ways to fight off the competition, like quality strains, extensive libraries, consistent supply - all will ingratiate you with smart shops. Growing better helps tremendously, if your goods look better, smell stronger and taste like more…
There is the best level. Not all potheads are dispensary owners, but all (good) dispensary owners are POTHEADS. If you have the meds that they have to have, well, who's the boss then? When it's really a drug, there is an innate disadvantage on the buyers side...