I find that a lot of it depends on how wealthy the area is. Here in the bay, in the rich areas of Oakland and oter cities, it can be $20 a gram, and even more. On the flipside, when I'm down in Santa Cruz, $10 a gram is on the high end of the scale. This is probably because of A. The university (UCSC), and B. Santa Cruz, while not a poor city by any stretch, is still off in the sticks a bit, and tends to collect more people who are down on their luck than say Piedmont (super rich city in the middle of Oakland) does.

Also, how strict the laws are in that area have a major influence. White Widow in Kentucky and White Widow in SF are going to be different prices simply because SF is a lot more lenient when it comes to cannabis than Kentucky is, and so growers/dealers don't have to take as much risk, and that usually means a lower overhead.