There is a great deal of uncertainty and ambiguity that surrounds the notion of prices in our modern society. First, we must start with an understanding of what price is. In order to do so, I will first outline what it means for something to have value. Value can be considered as a relationship between people and objects or services. For example, if Person A has two apples, yet desires three apples then he would consider trading one apple for something else which would yield him three apples overall (in this case a second apple). Thus the object which Person A trades away has "value" to him because he values having more than one apple but not at the expense of giving up two (which would lower his total from four down to two). This illustrates that there are different levels at which value can exist: Individual, societal-wide and international; each level building upon the previous one allowing humans greater flexibility in their decision making processes as they trade their way towards maximizing happiness given various constraints.
Continuing with the discussion of value, we must now consider what it means for something to be an "object" and how this applies. Many things can have value in themselves without needing any external influence or input (such as a human's life). However, once they are traded on markets then their values changes based upon market conditions. This is due to two factors: 1) The subjective preferences that each individual has over different objects which vary from person to person; and 2) The fact that humans need other humans in order for them to survive and thrive, thus giving those humans who provide goods and services a higher demand since they offer benefits not available through other means (for example food). Therefore if Person A needs 3 apples but only has one apple he will trade his single apple for another good/service (i.e., a second apple) instead of trading it away directly for cash money (not because he dislikes the idea of having money per se but rather because he does not want to give up something else in order get more apples overall).
Now that we have established what it means for something to be an object, and how value can change, we must examine humans' subjective preferences in order to understand the nature of money. Some things which humans desire are essential (for example food) whereas others are non-essential (luxury goods such as caviar); this is important because if a person's basic needs go unmet then he or she will cease living altogether.
Since humans need other humans in order to survive and thrive, they cannot simply rely on their own subjective preferences when trading with others since this would limit the amount of goods and services that they could gain. Hence a common metric must be created so that all parties involved can agree upon what is being traded; for example if Person A values apples more than oranges then he will trade away his single apple for two oranges (rather than cash money) because doing so allows him to get more overall satisfaction (four apples). This illustrates how cash money becomes an objective standard (which creates value out of sheer demand alone), which all individuals can use as a means of exchange even though their personal preferences vary.
In conclusion, humans have created money as a way to facilitate exchange (i.e., trading) in order to get what they need and want the most; which can be considered an objective good because it serves as a means of survival for all individuals by allowing them access to other goods that they might otherwise not be able to acquire.