先前空間價格的研究在市場範圍為固定的假設下比較兩種單一定價策略經濟效益的優劣關係。但真實世界裡，廠商所面臨的市場規模總是因外在條件的影響而不斷的在改變，可能萎縮或者擴張。是以，先前研究採取固定市場範圍的假設似乎無法滿足真實世界的情況。為了釐清市場規模變化對廠商採取單一定價策略的影響，本文擬在非線型需求函數的假設下，藉由設定市場規模的大小，檢視FOB和CIF定價策略的產出、利潤，消費者剩餘和社會福利，並且比較兩者間的優劣關係。 結果發現，隨著受限制市場規模的增加，採取CIF定價策略廠商的最適價格會跟著增加，但採取FOB定價策略廠商的最適價格會遞減。此外，重要的是我們發現在市場規模變動的假設下，先前研究有關兩種單一定價策略經濟效益優劣關係的結論將不再成立。換言之，市場規模的變化情形在空間定價領域中著實扮演著極重要的角色。 Although prior studies on simple monopoly spatial price theory have bend conducted in a world with fixed market area, a firm in the real world often confronts the market with various sizes. In order to fully understand that how does the firm react to the market size vary, this paper attempts to examine the relative economic advantages under alternative pricing policies in a world with two basic assumptions. One is non-linear demand function and another is the market size, which is treated as a parameter in the model. We will show that as the market size increases, the optimal uniform delivered price increases, but the optimal price under mill pricing decreases. Moreover and more importantly, we will show that in a world with varying market size, some findings obtained by prior studies in regard to the economic benefit comparison between alternative pricing policies no longer hold.
