In reply to lewiz:
Do you mean you want to put your phone IN the bag? With the chalk? Or are you looking for one with a zipper pocket attached?
If the former I have one that might do for you. It's yellow, Wild Country and is about 6 inches deep and 5 inches diameter. No idea what it might have cost - got it as a gift but I have enough chalk bags so if it sounds any good to you I could send it to you for . . what? . . . £8 including postage?