The cost of few missiles is peanuts compared with the cost to UK companies not being able to get oil out of Libya.
You're wrong to say the European Union is not contributing, and who knows what is going on behind the scenes, just because Germany for example isn't up front doesn't mean that they arn't helping to fund the exercise.
Coalition forces
US: Cruise missiles fired from USS Barry and USS Stout; amphibious warships, submarines and command-and-control ship USS Mount Whitney. Air strikes by fighter jets and B-2 stealth bombers
France: Air strikes by Mirage fighters and Rafale jets; Awacs surveillance plane; Charles de Gaulle aircraft carrier sailing
UK: Missiles fired from submarines; Typhoon and Tornado jet fighters; surveillance planes; HMS Westminster and HMS Cumberland; Using Akrotiri military base in Cyprus
Italy: Nato base at Naples understood to be central hub; other Mediterranean bases made available
Canada: Six F-18 fighter jets and 140 personnel
Forces from Belgium, Denmark, Norway, Qatar Spain, ready to participate