These are often very expensive and made from leather and lamb's wool. I wanted to use up some of my stash, so I just grabbed some brown faux fur left over from a costume and a heavy brown cotton. The basic shape is 5"x11".
I embroidered the free trout design and the monogram (using the stitches on my machine) onto the fabric first. So, I cut a much bigger piece of cotton than I needed. I trimmed it down to size after embroidering the design so that I could have it centered the way I wanted. You can just use printed fabric and skip the embroidery or hand-embroider if you don't have a machine. I cut 1 piece wooly faux fur 5"x11" and 1 piece cotton 5"x11"
Now you need to put on snaps or velcro. I used velcro because it's cheap and I already had it in my studio. I can't find my heavy snap setter anywhere, so I'm temporarily not using snaps. They would look really nice on this project though. I just cut velcro into 1" squares.
Stitch down the velcro. I use an X stitching to make sure it stays in place. It got a little knotty here, but after a nice trimming, it will look just fine.
The wallet folds up nicely and closes easily with the velcro. It took about 10 minutes to sew these, excluding the embroidery.