"The price of every thing rises and falls from time to time and place to place; and with every such change the purchasing power of money changes so far as that thing goes"

This quote by Alfred Marshall is describing the concept of cost flexibility, which is the idea that the price of a great or service is affected by the demand for it. Marshall is saying that the price of a good or service can vary depending on the time and location, which this variation can affect the acquiring power of cash. For example, if the cost of a great or service increases, then the buying power of money reduces, as it takes more money to purchase the same excellent or service. On the other hand, if the rate of a good or service reductions, then the buying power of cash increases, as it takes less money to purchase the very same excellent or service. Marshall's quote is a pointer that the rate of items and services is continuously changing, which this can have a result on the buying power of money.