This has been previously advertised on HUKD but they ran out of stock (http://www.hotukdeals.com/deals/80-mega-marble-mountain-only-2-99-works-2094452). Just letting you know it is back in stock now @ £3.99 but with 25% off with the code TODAY25 making it £2.99. Just ordered mine and got free delivery included (to the store near me).
Happy with this as its a great price. Hope this helps someone looking for marble run toys.