I wish people would tell me where I could find stuff that cheap. Really - anyone saying 2-4, 5, 6 - please tell me where I can buy 'em. I've hardly seen any for weeks, and when I have seen it, it's been 10 or more.
I know, right? I don't understand why there's lots of people keen to say e.g. "42r for diamond? That's a complete rip-off - you can get 'em for 30!" yet these people can never show you where. Things are "worth" whatever people will pay for them. It's supply-and-demand. As far as I can see, nobody has gunpowder in stock. So the price goes up. Go kill some creepers.
Some days ago... I went to smp 2 wild with a Looting III Sword. Returned with 7 stacks of gunpowder... not really hard to get as long as people arent filling their Grinders
True. But most people are too lazy to go to the wild; they don't want to get their hands dirty And there's lots of people with plenty of money who want sulphur - diamond-users want it for TNT, and the "big grinders" want to for splash potions. Supply and, indeed, demand.