I said for indies. Can CryEngine 3 or Unreal Engine 3 be used commercially for free?
unreal licensing http://www.udk.com/licensing
$99 Royalty bearing
$2,500 Per seat
In other words if you made a game to sell it is only $99 if your sales make $5000 or less.
"US $99 (Ninety Nine US Dollars) up-front, and a 0% royalty on you or your company's first $5,000 (US) in UDK related revenue, and a 25% royalty on UDK related revenue above $5,000 (US). "
But that is putting the cart before the horse. Get it and play with it. Changes are you will never actually make a commercial game so no biggie. But you you do make something amazing then the $2,500 will be a drop in the bucket compare to the profits.
the big draw of this over Unity is you get the full package. you have to pay for Unity Pro.