You won $500 million on the Powerball lottery. So how much is REALLY yours to keep?

It's still a pretty penny, but not as much as you might think.

So your multi-million dollar win is sitting in the bank and you're pretty happy about everything right now. But then your finance manager taps you on the shoulder. "I think there's something you should know..." she says. Forbes.com looks into a winner's money and comes out with some surprising options for you.