I made a crutch bag for a niece and one for the child of a friend. I just made a bag that narrows a little at the bottom. It had two straps with velcro to attach to the sides of the crutch above the handle. My niece found that if it hung from the handle it made it difficult to grip the crutch. The bag had a pocket on the outside. I just cut three pieces of heavy fabric (I used upholstery fabric. ) One of the pieces was not as long as the other two and when hemmed it formed the outer pocket. I sewed the three together, turned it inside out, hemmed the top and added the straps. Both young ladies said they were perfect. Neither said they caused problems with the crutch or knocked them off balance.