I love red lentil bolognese, just substitute the mince with them and cook as normal. I use a beef stock cube for more flavour but obviously leave that out if you are veggie.
Chickpea curry is good, there's a few recipes on BBC food, all you need is a tin of chickpeas, pasatta, an onion and spices. The recipes normally ask for fresh ginger and garlic but work as well with ground.
My DD has been buying loads of cake mixes, nice ones like ginger loaf cake.
Tuna pasta, you just add a tin of tuna to some tomato sauce, sweetcorn is optional. You can then bake with cheese on top or just serve from the pot. It's also nice with some cream cheese stirred through it.
I always have a couple of tins of evaporated milk, I just use it in coffee and find it nicer than UHT.
Do you have freezer space?
Part baked baguettes and rolls are cheap if you buy the supermarket own brand and have a good shelf life.