The debate about the ‘just price’ has ancient origin and returns forcefully to the scene when, in the event of crises of various kinds, there is a rapid and significant increase in prices of given goods or services. The main issue is whether price increases of such a nature could, or should, be considered illicit and ground the issue of sanctions against the firms increasing prices, thus focusing on a macro-systemic level of analysis. The central part of the article reviews different theories on what a ‘just price’ should be and focuses on the idea that a price is ‘just’ when it functions as an index of relative scarcity in free markets. It is claimed that such a function deserves protection by Italian and EU law. Therefore price adjustments in response to shocks cannot and should not be considered illegal: it is unacceptable to sanction private firms by attributing them the wrong of not having substituted themselves, at their own expense, for the exercise of a public function (that of making sure that price increases do not put at risk solidarity and other constitutional principles).