Heat a large skillet over medium-high heat.
Add sausage; sauté for 6 minutes, stirring to crumble.
Remove sausage from pan; drain.
Wipe pan clean; return to medium-high heat.
Add oil to pan; swirl.
Add onion, and sauté 4 minutes.
Add garlic; sauté 1 minute.
Stir in sausage, marinara, and 1/3 cup water; bring to a boil.
Reduce heat; simmer 20 minutes.2.
Bring remaining 2 cups water and milk to a boil in a medium saucepan over medium heat; reduce heat to low.
Gradually add polenta, and cook for 3 minutes or until thick, stirring constantly.
Remove from heat; stir in cheese and pepper.
Serve with sausage mixture; top with parsley.
Total price: $9.80 for 4 and $2.45/serving