This paper reports the first empirical test of a question long debated by managers across industries: Is it better to show my prices upfront or later in a purchase process? Specifically, we report three field experiments, conducted offline and online with a leading retailer of household appliances and consumer electronics, in which prices were communicated to thousands of shoppers alongside the corresponding product or with a minimal delay. These experiments consistently show that timing the disclosure of prices matters, in so far that it has statistically and economically significant impact on sales revenue. However, surprisingly, while delaying prices had a positive effect when consumers approached the retailer, the effect was negative when the retailer took the initiative. We use this evidence to describe a conceptual model and propose ways in which marketing research can contribute further to the ongoing debate.