Someone may have already suggested this but…
I just got a new cell phone last week and noticed that it was 4 inches long x 1 1/2 inches wide x approximately 1/2 inch thick…so I got out some of my 4 x 4 gauge-swatches and folded them in half then stitched up the side and bottom (L- shaped seam) and then attached i-cord and knitted about 4 inches then by knitting back and forth on the three stitches that I increased to four making a tab with a tiny button hole (by yo in the middle of the flattened part)so that I could loop it over the handle of my pocket book, sewed a button at the other side on top and I have a great cell phone carrier. I had made others but now this is so easy I have one to match almost every outfit and I don’t have to fish the phone out of the bottom of the pocket book when it rings.
My students at school (high school) like them so much they want to buy them.