I make my own sausage from scratch, I make a cumberland style, breakfast, country, italian, brats, polish, etc. There are many sausage recipe out there. Do a search on vension sausage.
I do like the Hi Country Salami mix though. It's the only pre-mixed sausage recipe I use. (It's a cooked salami, not a true dried salami)
Use a good grinder, some butcher shops will grind for you if you don't have a grinder.
I use a stuffer to stuff casings, I tried the stuffer attachment on my grinder, wasn't impressed. I use a 1-1/2 hp Cabelas grinder and stuff with a 5 lb lem vertical stuffer. It's awesome.
Food safety is something to be very aware of. Especially if your dealing with smoked sausages that aren't fully cooked. You have to use the right curing salts - prague #1, or #2. Kits will have the right stuff in the sausage mix.