These foods pack the most nutrition for the lowest cost. They contain fiber, important nutrients like B vitamins and iron and are low in added sugar, so they fill you up without that groggy feeling.
Breakfast cereal
Oatmeal
Puffed corn 
puffed whole grain
shredded wheat
toasted oat cereal
Read the nutrition facts
Low sugar: Pick a whole grain cereal with the lowest sugar content.
High fiber: Try for at least three grams of fiber per serving.
Lower sodium (salt): Look for a cereal with less than 210 mg of sodium per serving.
Bread and pasta
Read the nutrition facts
Low sodium (salt): Pick whole grain bread or pasta with the lowest sodium content.
High fiber: Try for at least 2 grams of fiber per serving in bread
and 5 grams in pasta.
Rice and Other Grains
barley 
brown rice
bulgur Top tips
See EWG's Cereal Report to learn more.
Don't be fooled. Read the label. Make sure the word "whole" is in the very first ingredient listed. "Multi-grain" or "wheat" isn't enough. Just because it looks brown, doesn't mean it's whole grain.
Start kids off right with whole grains, not white bread and white pasta. If they're not used to whole grains, mix them in gradually.
Buy in bulk and stock up during sales. Make your own oatmeal (See Recipes). Packets cost more and are often loaded with salt and sugar. Buy brown rice in bulk and mix with white rice if needed to lower cost. Buy whole grain bread on sale and save in the freezer.
Ready for something new? Try quinoa instead of rice. Look for it on sale or in bulk (See recipes).