Pictured here is your face when you see the prices.
Sit down and take a moment, because the real-cash Auction House for Diablo III is live (for USA anyway - Blizzard is waiting on South America and Europe for now). And the prices for some of those items might leave you slightly short of breath. As mentioned before, now that your Battle.net account is going to be trading around real (or semi-real) money, you will have to go through PayPal or Battle.net Balance, which probably means getting an authenticator app or device. Commodities are not yet up either, but are due in time. And, again as mentioned before, Blizzard takes a cut off the top.