In this work the problematic issue of price determination in economic theory is re-examined. In the first chapter a state-of-the-art survey regarding the existence of equilibrium and the structure of the equilibrium set in price-setting games is provided. In chapter two a new core concept, the Bertrand core, is introduced and characterized. In chapter three a revealed preference perspective upon the Nash equilibria in price-setting games is provided. In chapter four, the issue of Bayesian equilibrium existence is addressed when traders have incomplete information regarding each others' types. Finally, a summary of possible future avenues for research in this area is provided.