Fodor's Travel Talk Forums - Best Sim Card for Germany & a Few Days in Amsterdam

Friends will be in Germany for about 2 weeks and then in Amsterdam for a couple days at the end. One person is a 28 yr old who will likely text alot and surf the internet. It's not likely he will be making phone calls to the USA. Perhaps a few calls within Germany. The other person, his father, will need to make at least daily calls back to the USA. He will also make some calls domestically. He is aware of whats app etc. He may use iMessage to some degree, but wants other possibities. He will also text some and use the interent. Any suggestions for which sim cards they should buy. They both have unlocked iPhones. Thanks