thanks!
sorry for the long post, I wasn't sure how much info was needed, because until now I have managed to learn so little. these shop assistant can't speak high german, apparently and my swiss german ist simply not adequate for such technical details. so I just watch their lips move...
actually until now I had iphone 3G (now broken and too expensive to mend) and am not considering leaving apple for anything in the world
at the apple store you can buy iphone 4 for 649 which I find not cheap but acceptable with a prepaid if this helps me dodge a tyrannical contract.
so it seems they have it cheaper than the providers??