You can buy sausage for about the same $ as making your own. But when making your own sausage, you control what goes into it. For my first try I bought English roast (BOGO) and trimmed all the surface fat off which produced a very lean ground meat. Then I blended in a commercial seasoning kit and stuffed the casings.
This is my smoker, I have the door open because I put too many hickory chips on the charcoal and I want a thin blue smoke. The sausages on the left are summer sausage and the sausages on the right are venison hot Italian sausage. Both turned out Grrrrr8. I kept one summer sausage and gave the rest to my kids and the Italian sausage to a friend. All the sausage lasted about one day.