Which one should be given first? Commodity/service first, or the Price of the commodity/service first ?

Friends, you have heard the familiar question of: "Which one came first---Chicken or the egg?" Likewise, I am asking the above question to you. This question first arose in my mind while paying a man for some work he was supposed to do for me. Then I found this question applicable in most of the fields---everywhere--- where I go and pay money to anyone.