My easiest (&cheapest) dinner is bolognese.
1kg mince (beef/lamb whatever is on special)
1kg frozen mixed veg (small chopped pieces work best)
Jar of spaghetti sauce or large tin of chopped tomatoes
Tablespoon or 2 of tomato paste
One onion, chopped

Brown onion & mince, add everything else and let simmer.
Brilliant for the slow cooker or about 20 mins on stovetop.

Makes heaps, so there is plenty left over for lunches or a second dinner.
Can be used for pasta, shepherds pie, savoury mince & rice...