Easily 1mil, probably more. Not that I can draw, but I definitely know good quality art when I see it. When pricing something, take account the time and effort you put into it. You can compare your work to others' art and their prices here...
I've started somewhat of a directory. You can compare your quality vs. price to other artists there. It's a growing idea. XD Read it through. Feel free to join if you want.
Anyway.
That's a really awesome drawing. Now that I think about it, you could probably charge 5mil and I wouldn't think that ridiculous. There's many people who'd be willing to pay that for something like this. ^^