Slow Cooker Spaghetti Sauce

Bahan-bahan (7 porsi)

• 1 yellow onion ($0.32)
• 4 cloves garlic ($0.32)
• 2 28 oz . cans crushed tomatoes ($2.00)
• 1 6 oz . can tomato paste ($0.69)
• 1 Tbsp dried basil ($0.30)
• 1.5 tsp dried oregano ($0.15)
• 1 Tbsp brown sugar ($0.03)
• 1 Tbsp balsamic vinegar ($0.14)
• 4 Tbsp butter ($0.40)
• 1 tsp salt (to taste, $0.05)