Otto Neurath and Piero Sraffa, both of whom could be identified as having strong associations with Marxism, if in unorthodox fashion, offered up two of the most important critiques of the conventional understanding and treatment of the role of prices in economic thought over the course of the twentieth century. At first blush one might cast both of these critiques within the context of their criticism of capitalism as an economic system. Yet the differences in their approach to the ‘problem with prices’ are perhaps as striking as their commonly held depiction of a diminished place for prices in analyzing the operation of the economy. How they made their distinctive cases is the subject of this chapter.