What would be a filling meal for someone who doesn't have a lot of money?

I am not really able to make a living for myself, much less my girlfriend and me. I know the components of a healthy meal but do not have the income to eat this way.

I am finding it harder to get a filling meal, I’ve tried real actual grains like oatmeal and they are not very effective in staving off hunger. I mostly eat from cans. I am a diabetic and hunger can have real consequences. I don’t see how anyone can survive when perpetually hungry; even if they get one reasonably good meal a day.

The way things are, I have about $5—$10 a day for food and basic necessities, which doesn’t cut it. Even when I spend over $20 at the grocery store, I find that its still not a lot to eat.

So, what is suggested, for getting full and getting some energy to not amble around faint and listless?