How much for just the asteroid?

Asterank is an economic and scientific catalog of over 580,000 asteroids in our solar system.

I can’t vouch for the accuracy of the site (just stumbled across it myself), but it’s an interesting idea. The most valuable asteroids are worth more than $100 trillion a pop; the most cost effective asteroids in the neighborhood of $40 trillion each. I doubt, though, that these take into account the fact that if you mine many tons of, say, platinum from an asteroid and drop it into the terrestrial market, the market will get flooded and the price will drop.

Of course, if a large source of platinum was suddenly found, a lot more uses for the stuff would be found, demand would go up, and the price would rise again.