In reply to aln:
I was in Malta this summer (short trip, four days, cut down to three because EasyJet overbooked the plane).
Anyway, we ate out for all meals as we didn't have any catering facilities and it was such a short trip, and I remember thinking it was much cheaper than the UK.
I don't remember the exact amounts, but I feel like me and my wife paid £50 for an evening meal in a nice place, with booze and desert. Way cheaper than London.
My hire car was £8 per day. plus a £40 charge because the credit cars was in my wife's name. They have a rule for everything.
Parking is free, except for a small tip for the attendant guy that looks after your car.
Don't remember the price of the diving trips we went on.
I didn't shop in supermarkets, but I expect it to be cheaper than here.
My advice, work out what you spend in the UK, assume it's the same, add any excursions and you're probably on the safe side.
Most attractions are free anyway. The old city for example.
Don't bother with the pop-eye set village thing. Over priced and boring and full of people.