This research paper should explore at the concept and theory of Price Differentiation (different prices for an identical product in different countries, but within an economic union), as it is applied by online retailers (specifically Amazon), mostly focused on the EU market. It should look at the motivation for Price Differentiation and collect evidence of its existence from economics academic research (mostly EU and US research sources). This research paper will be supported by an analysis of data collected related to Amazon pricing in Italy and Ireland, focused on a set of identical retail products including mens apparel, mens and womens footwear, alcohol, soft drinks, stationery, mens and womens hygiene products, nutraceuticals (vitamins), books, jewellery, home goods, household products, technology support products. The data to be analysed have been corrected for different tax/excise regimes and are independent of shipping/currency differences (these have been controlled for). The research paper should explain Amazons stated pricing policy and any evidence of deviation from this policy. It should outline evidence of Price Differentiation in online selling as it relates to the types of products listed above, which has been identified by other academic researchers. It should also consider the consequences of price differentiation in terms of concepts such as the pink tax. It should consider implications of price differentiation for markets.