I thought this was a great project to introduce my girls (and their cousin who was over for the afternoon) to hand-sewing and sewing on buttons, so I tweaked the tutorial a little. First I used that flat elastic you purchase by-the-yard - it was about $.39 a yard, and I got 2 headbands and had some leftover from yard, so less than 20 cents a headband. I'm not sure how much the stretch headbands you purchase run, but I thought this was a good deal. But mainly I wanted the girls to work on something flat because I thought it'd be easier for them. I cut 19 inches of elastic and overlapped it about 1/2 inch when I sewed it together.
I had them choose all their buttons - I helped my 3 year old so her's is the all-pink pattern that I thought was cute. The older girls picked color combos and patterns that I wouldn't have, but that's the fun of letting them craft themselves.