This article argues that the price obtainable in an open market provides the best standard for determining the justice or injustice of the price of a product. The article argues that this standard, which is closely related to positions which have been held for hundreds of years, is superior to several alternative conceptions of the just price that have been put forward in recent years and is not subject to fundamental criticisms which can be addressed to them. The article also (...) shows how this standard is grounded in more fundamental principles of justice such as desert and equality. (shrink)