I have been going on girls holidays for the past 7 years and I generally reckon on £50 a day so £700 for a fortnight. I am going to St An this year and am going to take a little extra, perhaps £750 because of the cost of going to the big clubs but certainly nowhere in the region of £1000. I reckon, as you say, going to a big club will be the exception rather than the norm. Don't plan to drink in the big clubs, as another poster said 'I'd rather drink the foam than pay €10 for a water!' The disco bars in the West End are a good laugh I've heard. They are open till six and are not expensive.
We always eat out in the evening but probably only once or twice will we eat out at lunchtime. We go to the supermarket at the beginning of the holiday & stock up on loads of booze, snacks, crisps stuff to make sandwiches etc so most days we'll just eat that during the day, it wastes less valuable sunbathing time and the fridge is the nearest place to crawl if you have a hangover! We always start the evening drinking in the apartment as we are getting ready (although I guess us being girls that takes longer than you!) Then we don't have to buy as many drinks when out. We do buy a lot of drinks round the pool during the day tho. As I say we eat out every night and we go out pubbing/clubbing just about every night too, prob 12 nights out of 14. Each holiday we always go on about 3 trips out during the day too, boat trip, jeep safari, whatever.
As I say, every girls holiday I have been on so far all of this has come within £50 per day so far. I always take my credit card with me just in case, you don't want to run out of money on holiday so if you don't have a credit card it would be sensible to take extra. But my feeling is if I took £1000 I would find silly ways to spend £1000! I only put things on my credit card if I really have to!
Probably the best plan is to find out how much your mates are taking. It's irritating to go away with somebody who has got a lot less than you cos then they're always watching the pennies! It's equally annoying if one of your mates has got a lot more and is constantly flashing the cash!