Yeah it's always surprising when I hear Americans say that eating healthy is more expensive that eating fast food / eating unhealthy.

When I was veggie and just eating vegetables I could buy a week's worth of food for about £10 a Kilogram of carrots was about 50p potatoes were 60p/kg brocoli and salad item were a little bit under £1/kg

Then as you said basic things like pasta is pretty cheap, I used to get 1kg of pasta for 30p and then a jar of tomato pasta sauce for 60p and that could last me 3 meals.