I have an apple ipod nano and had to buy a case for it.
I choose this very basic plain case logic pouch over all the fancy ones because it was cheap and garneted to last for two years as stated by the manufacture.
The case logic universal mp3 play pouch cost £3.99 from amazon uk. It reminds me off a sleeping bag by the look and feel of it. The pouch is 11cm tall and 8cm wide, it will hold most models of ipods , mps players, and sandisks. Made from nylon padded fabric and can even be washed in the washing machine witch mines has a few times as i have a white one and gets quite grubby. Because the pouch is padded it gives complete protection on my nano. There is a metal loop that can be attached to anything bags, lanyards, keyrings belt loops etc i currently use it with my lanyard so i can use it around my neck when out walking. The pouch also has a toggle pull in fastner to hold the mp3 play in place when not in use.
As this is for an mp3 player it does also hold some models of mobile phones.
This may be a cheap basic mp3 sleeping bag but it certainly does it protects and keep my nano safe when in my bag or out hill walking.
I would highly recommend the case logic universal mp3 player pouch.