Unfortunately, consuming data while roaming tends to get extremely expensive very quickly. Recently, U.S. carriers have become a lot more reasonable with data plans, but it’s far from perfect. Usually, you pay about $25 for 100 MBs of data. In comparison, Verizon charges $70 for 4,000 MBs of data in the U.S. So 100 MBs tend to get used up quickly, especially if you use media-intensive apps like Instagram, Facebook, or Path.
In addition, international calling and texting plans tend to be really expensive, even if you aren’t actually trying to use them. At least with AT&T, you are charged when someone leaves you a voicemail, regardless if you wait until returning home to listen to the voicemail. To me, that’s crazy. If someone leaves you a 10-minute voicemail, you pay $10.
There are some small settings on your iPhone you can change to protect yourself from unnecessary charges while traveling. Here are the ones I toggle when going out of the country:
Click Here to read the complete step by step instructions @ techcrunch.com