But if you're curious re:prices, you can call the dealer listed on Controller.com as selling a 777. He's actually got several for sale in that neighborhood (and is super friendly, too - Eric).
On the cash front, ferry flights to the US are the biggest expense by far. A 777 burns ~$10,000 in fuel per hour, so positioning from (say) Asia to a boneyard in California adds up quickly... with crew, ferry insurance, landing fees & sundries you end up at $200-$250k. Parking runs around $3-5k per month in the desert, too.
I figure if you're starting at, say, $150k to ferry it, might as well fill it with some junk.
Ferry permits can be issued to airplanes “not airworthy and operating outside their certified range” if I am not mistaken.
Incidentally though, the FAA minimum liability coverage for a widebody is $750 million, and the policies I've seen do allow for cargo onboard (though not passengers).
Also, is it possible to buy non-airworthy ones and fix them up and sell them as air worthy ones? Or is it too expensive?