The guy who said pasta was spot on, it's not only very easy, very filling and pretty cheap - learning to make a good sauce will teach you some good fundamentals of cookery.
If you're on your own, a tin of tomatoes will always be too much for one meal - so it's perfect for having dinner and enough to put into a tupperware for lunch the next day. Great cold or microwaved.
Forget buying jars of sauce it's a total rip off.
Drain the juices out of a tin of plum tomatoes, then hold it over the sink, stick a knife in it and move it back and forth really rapidly to make the base. The tomatoes themselves have so much juice in it'll still be very liquid when you chop them up even if you drained every bit of the juices in the tin you could, if you don't drain them it'll be way too liquid. Just add some tomato puree and that's basically a tomato sauce. Add herbs if you like, a pinch of salt, a pinch of sugar and that's the base of a sauce, just takes time to simmer together.
There are so many variations on a sauce you can do anything you want. If you want a really easy but really nice recipe try this:
Chop half an onion or a couple of shallots and fry them in oil, if you have a jar of anchovies in olive oil - use some of that oil as it really makes the dish.
Chop up anything between 2 and 6 anchovies very fine and add them to the onions when they are bleeding.
Add a tin of tuna, drained. Use the type in oil preferably.
Follow the basic guidelines for the sauce - pour in the drained and chopped up plum tomatoes, add a squirt of puree, salt, sugar. Now add a splash of balsamic vinegar if you have it and a generous amount of dried oregano, and a teaspoon or too of chopped capers.
EDIT - you may not need salt as anchovies are very salty, and make sure you drain the capers of brine or the dish will be too salty. Leave salt to the end to see if it needs it.
You can add different stuff here if you like - I liked to finely chop a tin of smoked mussels and add them but its an expensive luxury.1
Simmer it for at least 15 minutes, then put the pasta on to boil with some salt in the water.
You want the pasta to still have a bit of bite to it - don't cook it until it's totally sloppy and soft. While it's boiling, test the sauce a few times and get the mix of flavours right adding a bit more of the oregano, salt, sugar, balsamic etc if you think it needs it.
When the pasta is done drain it (not too thoroughly as a lot of liquid will have evaporated from the sauce and a little from the pasta will be nice) and put it on top of the sauce and fold/stir it in.
If you have some nice quality olive oil, add a little drizzle raw at the end and stir it through for flavour, and it gives the dish a glimmering shine.
That probably sounds more complicated than it is - but it's just chopping stuff and adding it at different points. There's no precise timings anywhere.
