You will need:
Plastic Bag String, or plain yarn (I used standard plastic bags. You can learn how to crochet with plastic bags here
Crochet Hook (I used size I. You can adjust as needed)
Tapestry Needle (the super cheap, big plastic kind)
Button (I used a cover-your-own so it would match)
I used 9 bags for this project. The strips shown above are from just 4 bags.
The crochet stitches used are chain stitch, single crochet, and double crochet. A whip-stitch is also used.