I make homemade sauce:
I brown a pound-and-a-half or so of ground beef in a big pot, drain off the fat, then add one huge can of crushed tomatoes, a can of "italian style-diced tomatoes with garlic and herbs and olive oil", a small can of chopped olives, a fork-full or so of finely chopped garlic (from the jar), and a can of tomato sauce. Then I add 1/2-3/4 of a box of beef stock (I go to the organic section and buy the all natural stuff - have to have no MSG). I let that simmer for at least an hour, maybe more, stirring frequently, till it is reduced and thick and delicious. Finally I season to taste with an Italian seasoning mix and then mix in lots of grated parmesan cheese.
The kids and DH like mushrooms, but I can't stand them, so sometimes I will spoon out some sauce for me and then add a can of mushrooms at the end of the cooking process.
For lasagna, I just layer this sauce, lasagna noodles, a mixture of mozzarella cheese and the "Italian" cheese blend you can buy pre-shredded and bagged, and a mixture of ricotta cheese, cottage cheese, an egg, and some herbs. I use LOTS of mozzarella, as DH likes things REALLY cheesy.