In my travels around the internet, I came across a tutorial for a very cute little bag with squared off corners. Here's how mine turned out, following that tutorial, and adding little tabs on either side of the bag.
I used pieces from a vintage sheet that also lives in my house as an apron. It's also in the process of being ripped up for a braided rag rug, but that will be another post (assuming I can figure out how to make it lie flat and I don't scrap the project). Very thrifty, yes?
The zipper is the only not-vintage part of my bag. It came from a fabulous Etsy shop called The Zipper Store. The prices are fabulous, and the shipping is so fast! I received my zippers on the east coast just two days after I ordered them from the CA shop. I am pleased. I may want to add a ribbon pull to the zipper... I'll check through my stash.
My finished bag is about 5" long, 3" wide, and 2.5" tall. Not perfect, but I like it!