Supply And Demand

I never realized how much supply and demand effected my life until one day I went to buy a snack from the store. I always buy the same exact thing from the same exact store and it is always the same exact price.  I got the snack and went to pay for it. Oddly enough I had to pay 85 cents instead of 75 cent. I was upset because I had a 5 dollar bill and 75 cents in my pocket. Also because the price had increased. I figured it was because there was a high demand for the snack, the suppliers raised the price. They may have figured people would be willing to buy their good, even if the price was higher. They were correct because I still buy that exact snack when I go to that exact store, but this time at their new price of 85 cents.