I just use a jar of spaghetti sauce of choice.
If I like the sauce thinner, I add a can of seasoned tomato sauce.
I also add a can of mushrooms,
one chopped fresh tomato,
and one chopped fresh bell pepper.
Throw in any additional seasoning ... bay leaves, basil ... whatever you prefer.
If you want meat in your sauce, brown 1 pound of ground beef (I usually add Mrs. Dash to the ground beef), drain the fat and add the meat to your sauce.
Simmer the sauce until the fresh tomatoes are cooked.
Voila. Sauce is done.
As for the pasta, just follow the instructions on the package. I'm not thrilled about pasta that's all mushy (overcooked, chances are someone is not following the directions). After draining the pasta, I like to coat mine with margerine. Add margerine to the hot pasta; as the margerine melts, toss the pasta to coat. I'm sure there are healthier ways to keep pasta from clumping (olive oil, maybe?). I'm ok with margerine.