I've wanted to make one of these box bags for a while, and this tutorial appealed because there are no raw edges left inside. It was awkward to do some parts, and I had made things harder for myself by using vinyl fabric, which got crumpled and couldn't be ironed flat. But it all worked out well in the end!
I got the outside fabric last month in County Fabrics, a treasure trove and highly recommended especially if you're thinking of curtains. The red lining fabric was bought in Ikea some time ago.