To survive on your basic necessities you need to have some sort of income. The income is the creation of wealth from less resources; whether this is receiving money for services and or time (job) or charity (foundation, government assistance, individual donation, etc).
Your income rate needs to exceed your spending rate for your needs or you will not survive. There are two sides to the equation. In coming (income) and Out going (expenses) are the sides and need and want are the insides.
Basic In-coming and Out-going Diagram



