The pink one is even easier. It's made from a pink silk camisole (to you men, that's a tank top) that I bought at Goodwill for a couple bucks and the bag is made from a really inexpensive remnant of brocade. The trick with making a shopping bag from a tank top is to find one really cheap (or free) that has the same neckline as the back line (i.e., not a scoop neck). If you find one like this, it's the perfect shopping bag and no need to hem the straps.
Turn the "stuff sack" inside out and sew it into the inside seam of the bag facing the top. Now, when you turn the "stuff sack" rite side out you can stuff the shopping bag inside. You can close your "stuff sack" with a drawstring, or as I did with the purple brocade, you can use a simple snap button.
They make great gifts and they're good for the environment. Plus, you're not paying $5 for a brand name "Chico Bag," which uses the same concept. And, if you're into it, you can make it much prettier than a chico bag!