For about $2,200 I can get you a matched set of American bison horns. Comes with an entire bison, no extra charge!
I have sawn horn with everything from a light coping saw, to a hack saw, to a carpentry saw. It's pretty easy to work. You can then shape with rasps, files, sandpaper, and even with a scraper. I have also used power tools like a dremel, tec. But you also risk burning the horn if you use high revolutions. Once burnt, you will need to scrape down under the brown stinky damage.
Then once it is smoothed out as nice as you can get it with 600 grit sandpaper, use some chalk on a strip of cloth and polish away. When it is as polished as you like, rub a little wax into that strip of cloth and a little more elbow work will make it glow!