Commodity computing is way of getting access to computer services like storage and processing power quickly, cheaply, and easily. It's like the supermarket, where you can go and buy all kinds of things (like bread, milk, cheese etc.) in one place. With commodity computing, you can "shop" for computing resources like storage and processing power, and buy only what you need. It's different from buying a computer, because you don't have to buy a lot of expensive hardware. Instead, you can just buy the amount you need. It's like buying apples, oranges, and bananas, instead of buying a whole box of fruit.