There are many kinds of bag, from many brands, expensive or not. But have you already think to create your own bag. With old stuff. It’s not expensive, and you can custom it as you wish.
That’s what I’m suggesting you: create your own bag!
The bag you can see on the above picture, is the one I made a year ago. It never broke, I made it with a rags and curtains in a patchwork style. And in my good habit: the nearly science!
But I offer you in that tutorial, objective dimensions.
Note: this tutorial is dedicated to people who knows already the sewing basics.