I love these peasant skirts because they are so easy. They do take a lot more fabric than you would expect, and for an adult one, I would buy at least 3 metres, although I would have enough leftover for a child's one too. The problem is that with each gathering layer, you need fabric a lot longer for the next one, so by the time you have 4 or 5 layers in an adult skirt, they are very long strips of fabric.
What makes these extra easy to make is my gathering presser foot for my sewing machine. It gathers as it attaches the two pieces together. Its a pain to use, and doesn't do the neatest of jobs, but for quick skirts like this it is fine, and really speeds things up. If I was making something with expensive fabric or that was to be really on show, I'd gather the "old" way - sewing a couple of rows of loose stitches, pulling the gather, sewing the fabric together.