If you process your own deer, why pay later to have somebody make sausage? If you get a meat grinder, there are tons of sausage recipes on the internet.
I made my own pork sausage for the first time recently, to avoid MSG, and to reduce the cost. It turned out pretty darn good, but next time I'll add a bit more fat, I have to add fat to the skillet or it sticks. It cooks up a bit dry if I'm not careful. And so it goes, it may not be perfect the first time, but you'll learn, and can adjust your recipe until you get it the way you like.
We get Boston butt pork roasts on sale a lot, I cut my own pork steaks from them, make ground pork, sausage, and use the irregular leftover pieces (if they don't get ground) either just roasted, with BBQ sauce, or use them when I cook a pot of beans.
Tough cuts of venison make nice burger, or use to make venison stew or chili and pressure can it.