Word. Right now is the WORST time of the year for trying to score some. Typically, all outdoor growing operations are done over the summer, harvested in Aug/Sept/Oct, thats why its so plentiful and cheaper in the fall/winter. Then as the commercial supply runs down in the spring/early summer, you start to see it dry up and slight price increases while sales drop b/c people who smoke hoard it for themselves. Even though it can be grown indoors year round, most of the stuff grown indoors is higher quality & much smaller harvests and therefore is often kept for personal use or sales to friends.
As for the effects of complete decriminalization (if it occured) I have a personal theory. If it was legalized, I think seed sales (initially) would shoot through the roof. Almost EVERYONE who smoked would be growing it in their closets, gardens, etc. Weed prices would drastically drop. This would almost surely decimate the tobacco industry (which is probably part of the reason weed is illegal, tobacco companies probably pay off congress to keep it illegal) and would actually increase general health in the USA. While its true that joints and cigarettes are about on par with each other in regards to effects on health, you have to realize that the average pot smoker is not going to smoke 15-40 joints a day as a tobacco smoker does with cigarettes. As tobacco smokers turned to pot, their amount of smoking would decrease, leading to decreases in lung cancer and other smoking related illnesses. Basically the only things keeping weed illegal are: The tobacco industry, Ill-informed geezers who currently hold this nations power, etc. Currently NORML is launching the biggest pro-marijuana legalization campaign in history. You can check out the details at http://www.norml.org/