According to a search in the Grand Exchange, it seems to be the Third Age Melee set, worth 357.7 millions. Information retrieved on March 22, 2011; prices vary over time.
Torva set
boardwalk and parkplace are the set but boardwalk is the most expensive.
Paris
The most expensive Lego kit/model is $500 Australian dollars.
If you want to show off your wealth, buy the most expensive god armor which is saradomin armour set (white trim) and costs 5894k (about 6 mill). If you cant afford that buy zamorak armour set (red trim) and costs 3930k(about 4 mill). And if you can even afford that then you can buy guthix armour set (green trim) and costs 2155k (about 2 mill).
its the death star, 399.99
The most expensive Lego set ever was the Lego set number 10179 ultimate collectors Millennium Falcon which originally sold for $500 on Lego.com.
Miracle Blade is one of the most expensive knife sets available. They have more expensive through their website, but they aren't sold in their stores.
Donald MacPherson's set sold for £30 000 after he died, that's the most expensive as far as I know
Click Set-up cannon stand. Your RuneScape character will automatically set up the rest.
The Most Expensive Set is The "Statue of Liberty" It Sells For 4997.97 USD, by Toys Trading Company. Below is the link.
The Mclaren F1 is the most expensive car ever at 11,800,000$. Or 11 million, 800 thousand $.That'll set you back A LOT