organic food..advice please

martha
ok everyone serious question please dont judge as im just trying to choose more healthier ways for my family. im not very educated on the matter..
where do you find organic foods? 
like does walmart sell it? im hearing and seeing alot of ppl getting very sick and it just makes me wonder if the foods we put in our bodies are causing some of these health problems.. also can we even call these "foods" food? is it nurishing our bodies or killing them??