Charging goes with German credit card not on the site, well, however the phone or via chat and jerk-twitch done. We always take the $ 40 - $ 50 month plan - depending on the length of stay. Aware mobile configuration: Just looking for "h2o settings" google (have the settings not to hand). And hey presto, you have already upon arrival at the terminal network.
Also interesting is Straight Talk, their cards at Walmart are exclusively available and also use the AT & T network. However, their activation by telephone must be done on site - and that's not just about the acquired card but only another phone.