This quote is significant because it describes how the ball field will pay for itself. Just as the field has embodied so many dreams for Ray and brought so much peace for him, the quote alludes to the idea that others will pay to experience the same. Salinger envisions how the field will turn a profit for Ray because it will trigger in others what it triggered for him. In Salinger's vision, individuals have money. Yet, the accumulation of wealth does not translate into the possession of peace and happiness. The field can provide that to these people because it will allow them to go back to a part of their lives where peace and happiness were present. To reclaim, if only for a moment, that small moment of happiness and peace is where people will willingly give their money for it is "money the have and peace they lack."
Another significant element to the quote exists in how it envisions the gap between money and happiness. Mark and Bluestein represent that money element, individuals who have more than enough, but yet cannot find the notion of peace that makes them content. The quote suggests that there are many who are like this in that they have wealth, but still yearn for something more. Ray's construction of the field and his reason for being in the world are what others will pay money for because of the potential for happiness that exists in this "field of" their "dreams."