"Online auction sites like eBay provide ways to measure what consumers buy and how much they pay. Does this imply that consumers pay similar prices, irrespective of their location? Comparing prices for homogeneous, tradable goods in the euro area and the United Kingdom, we find that prices differ significantly. The differential is not related to countries' having different currencies. However, price dispersion-the variance of prices-does seem to be smaller if two countries share a common currency. Our results confirm the importance of national borders in explaining price differences and their magnitude is related to (not) sharing a common currency." ("JEL" E30, E31, E50, F40) Copyright (c) 2009 Western Economic Association International.