There's no need to get quite so stressed about it all - you've got plenty of time yet - and I know you said you're definately applying this year, but really - what's wrong with applying in a possible gap year.
Apart from anything else - it is downright stupid to end up picking degree subjects out of blind panic to get everything out the way - even if you do want to avoid top up fees. Personally I think it's worth taking the time to work things out properly - and a gap year might allow you to experience things which shed a whole new light on life. especially considering you say you don't really have any interests in terms of study - a gap year might give you the experiences which spark off a specific interest.
BUT - if you are determined to apply now start thinking about the sort of person you are.
Are you a practical person - can you see yourself working outdoors/in a hands on job in the future?
Are you particularly academic?
Are you good at languages/maths/humanities or any other specific subject?
Do you get the feeling that once you are done with your A-levels you will just want to try something completely different - or do you like a specific area of your subjects so much you would love to carry it on?
Do you like the idea of working with people in some way - eg. social services/teaching etc? Or can you see yourself as some sort of enviromentalist/zoologist etc? Or maybe in business or similar?
Ask yourself these kinds of questions and then think about the sort of jobs that go with your answers (if you know what I mean). I say this - not so you can plan your future career - but because it would then be a good idea to go out and get some work experience in the areas you identify yourself having an interest in - to see if you really DO like working outside, or if actually - the reality is you're a bit of a wuss when it comes to mud and rain!
At the same time - just browse through ucas - from A-Z - any course name that makes you think - whats that? or - that sounds interesting? have a look at it in more detail - if it grabs your attention more then do some further research and do as I mentioned above - try to get some experience in it.
If you do all that then you are likely to find something for you (I know - it's what I did - so it works