you often these at markets and they can be quite pricey
its easy to make and all you need is some scrap fabrics and a pack of "self-cover buttons" which you can find at craft outlets - lots available online so do a google search. They come with instructions on how to use them.
i made these from the scrap fabrics that were left over after i did all the sewing for our cubby house project.
if you want further instructions - just leave me a comment