Looks good. I don't think $30 would be unreasonable. Maybe up to $50, but would depend on the area. Where I'm at walnut shorts aren't much more and might draw a higher price.
Only criticism, and I don't have much room to talk, on the front the grain doesn't match. I wouldn't even notice, but working on some stuff right now where I need to match the edge grain.
Really though, it's a good looking piece. I'd be proud to show it off. Love the finish; really brings out the grain of the oak.
https://www.amazon.com/gp/product/B07L6851X1/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
If you want to tap some 510 thread holes, but personally I would just put some 8mm'ish holes in the bottom. 510 threads in wood would just get stripped out and collect gunk and don't offer anything, but some small holes sunk into it makes them sit better (maybe you did do that; can't tell from the pic).