Hotels arent much i think about 30-45 euros a room but if you split that then it works out better. (x 4 nights overall)
Split petrol costs but its only a 1.6 so not too bad and cheaper on the continent
Then your miscellaneous money, food beer money etc, that is up to you how much you take
I have budgeted for 250-300.
Its not the cheapest trip ever, but how many holidays have a supersoaker xp240 as the 'weapon of choice'