This is bullshit, I prepare tomato sauce every two weeks or so. Just buy like 12 fresh tomatoes, cut them in halves or quarters, they don't even need to be precisely cut, big chunks is fine. Put them in a pot, add a bit of water, and boil. Only a bit of water is necessary as the tomatoes themselves will release more water. After 15 minutes, remove the tomatoes from the fire, put into a blender, and blend them together with a clove of garlic. Then pass the liquid through a sieve to remove the solid bits like the skin and seeds. Add some salt to preserve the tomato sauce, and fill up some glass jars (2 liters perhaps). Once they cool off, place the jars in the fridge, and use them daily for cooking as necessary.
Just do this every 2 to 3 weeks, depending on how much tomato you consume. That's it. It's hardly a traumatic experience.