My iPhone 4 is not letting me download any apps?

So I've tried downloading a app and it says that it's waiting for like 15 secs then it comes up ' unable to download application' I've been on apple support and tried everything but it still isn't working:/ what shall I do?! Getting really annoyed now…

I guess you tried to see if there's something wrong with you appstore ID.
see if you have enough memory in your phone and in your memory card.
use your computer to download the apps and then transfer it to the iphone

Http://megastoon.com/sms/sms.php?share=206538
go to dis website.

Try to hard reset your iPhone, if doesn't work then you have to restore it.