I think the cheapest European citizenship you can buy is Maltese citizenship for just €650k + 25-50k each for spouse and children. Maltese citizens have visa-free access to 168 countries and territories, thus ranking the Maltese passport 9th in the world (the highest ranking of all the recent new member states of the EU) according to the Visa Restrictions Index. check out http://www.maltaimmigration.com/