A few weeks ago I enjoyed sewing these things, using inexpensive girls t-shirts, under $3.00 apiece.
I bought two cotton t-shirts for each project, and cut one of the t-shirts into strips, the largest strip for the waistband. The pattern includes the waistband piece. The other strips were used to make ruffles on the shirt.
This Is a pre-pieced fabric. I would recommend making the skirt area much fuller, while keeping the waistband the right size.