The Cellz Leather Flip case costs £10.23 with free UK Shipping.
The above case is one of several designs of leather cases for the iPhone 5/5S that Cellz offer. The profile of the case is incredible thin and consequently I would imagine it could get marked or damaged fairly easily. But it is lovely nonetheless. I do like the inside sketchings.
You slide the phone into the case and the side pieces hold it really tightly. And then you just use the phone as before.