this tutorial, which is itself based on the reverse engineering of a bag she was given. My fabric must have been slightly thicker than hers because it's a really tight squeeze getting it into the strawberry corner.
I'd add some sparkly polka dots next time, since I don't have red spotted material but I do have fabric paint. And make the berry just a smidge bigger. I like the size of this bag. Much smaller and you can only fit one box of cereal in it. And sew my tag in before I put the sewing machine away.
Buy this one (with or without sparkly silver seeds) or order a custom bag at ShopLocket.