I've seen these around online before and wanted to try my hand at one. It was amazingly easy and not so expensive to make. I had the elastic on hand and the little bag of buttons I got at Walmart for about $2.
It was all hand sewn and the whole thing took about 30-45 (interrupted) minutes! The bag of buttons I got only had 4 colors and varieties. It would be really neat to get a bag of really random buttons and see what turns out. Also, if you have a little button collection, this would also be a great project.
Happy hand sewing!!