Well worth the 10$
Minecraft is cheap. It's full of potential. It does what few games succeed in doing. It makes manipulating the world around you 1. Challenging and 2. Pleasurable. It doesn't use and cheap tricks to devalue the experience, like flying, or Second Life crap. You start out with NOTHING and can do most anything. It never cheats it's own internal logic, and it's actually a pleasure to build and discover.
It's still in alpha, and already it's a phenomenon. Only when thinking about the cool stuff they're gonna add i get all tingly. No, really. This game could be MINDBLOWING when it arrives in full form, and then some.
Check out some youtube videos of it and you WILL be convinced.
Or check out the reddit page: