Pasta sauces are dead easy.
My basic - one stock cube, some PRE prepared garlic (very lazy is ideal) and a tin of tomatoes, then add some oregano or other dried herbs and simmer for about half an hour, add some water if you are worried it will stick.
You can then make a vegetable version - sauté any veg you want, then add the ingredients above and simmer. A classic base is onion, celery and carrot, then add tomatoes, stock etc. I make a nice chunky sauce with red pepper, mushroom and leek. You can blend if you don't like lumps.
To make spag Bol, brown the mince, add as above, simmer. You can then use it for lasagne, if you can't make a white sauce, you can use cottage cheese instead.
Jarred sauces actually taste vile. Once you start making your own, both the texture and the sweetness are not nice from a jar.
I've got some pasta bake and some chilli recipes too but I'll only put them up if you want them.