Sauté onion and garlic in olive oil for about 5 minutes. This is a great place to include other veggies for additional flavor. Red, yellow, or green peppers make a nice addition. Mushrooms or black olives too.
Add tomato sauce, oregano, salt, pepper, cheese sauce and water.
Cheese sauce can be almost any cheese sauce that pleases you. I often buy Kraft Cheese Sauce in a jar for a base for making dips. I also buy powdered cheddar from a local Amish store for small quantity needs like this one. A small chunk of velveeta and a bit of milk makes an acceptable mild cheese sauce.
Lower heat and simmer for 30 minutes or until it thickens.
If you are going to freeze the sauce for later use, let it cool to room temp and put it into plastic freezer bags. Put it in the freezer on a flat surface and it'll store well.
For meat sauce, just brown 1 lb of ground beef, the leaner the better. Adding minced onion, garlic powder, or a tablespoon of worcestershire while cooking adds a great flavor. Drain meat thoroughly and add to the sauce.
I don't recommend adding the meat to the sauce for freezing, freeze it meatless and prepare the meat when you use the sauce. Freezing ground beef in this sauce gives it a texture I don't like.