I loosely followed this tutorial
If you want a bunch of different patterns without having to by fabric by the yard, I recommend checking out the fat quarters and scrap section at your local fabric store. I bought some fat quarters for about $1 a piece and was able to get 3 sections from each piece.
All told, I spent about $15 and have enough material to make at least 30 of these for myself and friends.
The ripstop nylon was 7.99/yd.
I am using these every day and they work great for portioning out things like trail mix and carrying them in my purse.