I have been carrying my knitting projects around in plastic bags for decades. I like to have a certain number of supplies with me and years ago found a leather make-up case with a zipper (and a mirror) that is the perfect size for my scissors, needles and other tools.
I used this tutorial but enlarged it to accommodate my needle case, a pattern and a couple of balls of yarn. It is the perfect size - I love it!
It was so easy that I make a couple of more for fellow knitters. These are made from Denyse Schmidt Quilter's Quarters from Joann's Fabrics. One yard of fabric is printed with four coordinating fat quarters, so even choosing fabrics for these two bags was super simple.
Another bag I made turned out perfectly, but doesn't work well for knitting. I just wanted to try this tutorial which is very well written and nicely photographed. This is the largest size pouch and will likely be useful for something - I just don't know what it is yet!