why dont we all chip in?

Why dont we all chip in is an idiom phrased as a question which is asked of a group of people with helping out someone else, usually of a monetary value. This is often said to any group of people, such as work, school, neighbors, or family members at a party and primarily to help someone else with some type of financial struggle. It may also be to bring their money together and buy a more expensive item or gift for someone.