Frank discovered an app called What's App, but he's worried about traveling overseas and paying a ton of data roaming fees. He got a data bill of $700. Leo says if Frank calls up AT&T and tells them he's older and just learned to use a smartphone, they'll likely lower the bill this one time only. Then Leo recommends that he zero out his data meter on his iPhone when he goes overseas so he can monitor data use. That'll give him an argument with AT&T if the charge isn't what his iPhone says. He should also make sure to turn off data roaming until he needs it because some apps will use data without him knowing it.
If he's going to be somewhere for a longer time, it's cheaper to buy data locally with a temporary SIM card. He will also get a local number. He can also get a Wi-Fi card locally and use his iPhone on that.