Supply and Demand
Demand- the desire, willingness and ability to buy a good or service
Demand changes because the consumers need for that product or service becomes greater or lesser causing the demand to fluctuate.
Supply- the quantities of a good or service that producers are killing to see at all possible market prices.
If the demand for a good or service fluctuates, it causes a company to buy more or less of that product based on the need for that product thus increasing or decreasing their supply.
Equilibrium Price is the price at which the amount producers are willing to supply is equal to the amount consumers are willing to buy(demand).