What are staples to have in my kitchen/fridge/pantry?

I am single and really have no idea how to cook but I am tired of eating so much processed food and eating out. What items do you think are the best to have on hand at all times that are versatile? I'm not a vegetarian but don't usually eat meat (occional chicken/fish, but rarely). I also hate leftovers so I need ideas of things that don't go bad too quickly. Thanks!!