I saw an outfit like this in a posh little girl's clothing store and the price tag on the skirt was outrageous at almost $40. So I took a yard of fabric, sewed four straight lines and threaded some elastic through. The only difference that I can see is that the polka dots on the other skirt were bigger.
By-the-way...my fabric cost me $2. I had the elastic already, but if I had bought that, it would have been maybe $1.