You and your roommate both enjoy Blue Bunny cookie dough ice cream. At the campus store you can buy a pint of ice cream for $3. In your last visit to the store, you noticed Blue Bunny ice cream was on sale for 50% off. You are excited for the sale and stock up on pints of ice cream but to your surprise, your roommate purchases fewer pints of Blue Bunny, opting instead to purchase more of Ben and Jerry’s ice cream. Explain how each decision relates to concepts of income and substitution effects.