According to Bill Horne snipped-for-privacy@gmail.com:
That article offers some rather bad advice.
It suggests paying $50 for a 30 day T-Mobile international add-on. Assuming your phone isn't locked (VZ phones aren't, others may be) anywhere in Europe you can get a local SIM for about $20 which has vast amounts of data and generally has a deal to call the US for a few cents / minute. Under EU law, any EU SIM roams at no cost throughout the EU. If your first stop is in the UK, British SIMs mostly still roam for free in Europe and have the advantage that the instructions are in English.