Two topics...
Price: 5 minutes on the bandsaw, 30 minutes hand sanding, plus finishing time, plus time to glue up the blanks, plus material... your $30 price is way too low. Even if this is a retirement "hobby" you will probably find, at the end of the year, that you haven't covered the costs of your machinery, blades, glue, sandpaper, and other "overhead" expenses. I find that I need to look for at least $40 per hour (when I am not learning a new technique), and even that rate would not have earned enough to put my kid through college. Note that for every hour you "work" as a craftsman, you probably have an unpaid hour or two sweeping the shop (and other minimum wage tasks), and marketing.
Color. I am surprised how dark the ash has become... possibly the fine sanding dust from the walnut is getting embedded in the end grain, and is acting like a colored filler. Have you considered running the grain in the direction the cards sit, so the primary "show" is edge grain? The end grain would be at the bottom of the card groove (who cares) and at the top lip (where a darker line might be attractive). That may save a lot of sanding time, and would present a prettier grain to the viewer. It would create a weak spot where the foot connects, but you could dramatically reduce the back cut-out to compensate.
Despite my business critiques, it is a pretty holder!