At 69 pence a ball this is one cheap way to make a bag. On my recent UK trip I visited Leeds, a first for me and the local market was so good for knit and craft. Two balls of yarn and a few buttons at a fraction of the price if I'd purchased in my home town of Reading.
Not as strong as string but not far of for the feel and texture. I figured a Free form bag was the best thing to make. It has an almost grass/like like appearance, so some buttons in the shape of flowers and maybe a bright pink ribbon and then it will be finished.