How to set up an iPhone for international travel on AT&T

Traveling abroad with a smartphone plan is definitely confusing. You can have all the features you want pretty much as-is, but you have to be willing to pay for that convenience. In the worst-case scenario, it could literally bankrupt you if you're not careful. AT&T charges $0.0195/KB $0.002/KB for international roaming data, but don't be fooled by that small number. Your monthly phone plan at home might have 10GB included, but one tenth of that (1GB) in maps, music, youtube videos, and FaceTime calls (not unreasonable) while abroad will cost you $21,000 $1997. Whoops.

Update 2/23/2016:

• It looks like AT&T made some changes on Nov 13, 2015 in our favor to keep up with the competition! After Verizon made roaming to Mexico and Canada for short trips incredibly easy (an automatic $2/day for the same service as your home plan), AT&T made roaming in Mexico completely free! Unfortunately, no change in pricing for Canada.
• However, pay-per-use data cost seems to have come down, and this blog now reflects this. I could not find any evidence online of when this exactly happened (do any of you know?) so I assume it was at the same time as this other change. The new rate of $0.002/kB is $1997/GB which is 1/10 of the previous mind-boggling $21,000/GB. Still too high to use casually!
• Passport packages remain the same price

How do we get around this? Here are a variety of options that start with the simplest and safest for not having any overages, and slowly increase in service, cost, and complexity. Given your individual needs and budget, take a look and choose what's right for you! Most of these tips will be applicable to Verizon or T-Mobile plans, too. I tried to be comprehensive since I've never seen another website that lays it all out with detail.

Option	Voice Incoming / Outgoing	Text Incoming / Outgoing	Data	Capability	Difficulty	Cost
0. Turn off your phone	None / None	None / None	None	Paperweight	Low	Free
1. Airplane mode + WiFi	None / None	None / None	WiFi only	All your apps/camera with data on WiFi only	Low	Free
2. Data roaming off to have most phone functionality	Straight to voicemail / Outgoing works	No extra charge / $0.50 extra charge	WiFi only, but can turn on cellular data for extra charge (risky)	Most functions work; very popular	Med	Low
2A. Set up a Google Voice account				Like above with better voicemail		Low
2B. Turn on data roaming when needed				Get data on-the-go at risk of big bill		Low to High
2C. Use VoIP for voice calls				Cheap calls to back home		Low
3. Buy a travel data package	$1.00 to $0.35 per min based on plan	Unlimited	120MB to 800MB included based on plan	Full capability with controlled price	Low	Med
4. Get a local SIM card	Variable minutes included	Variable texts included	Variable data included	Full capability; same as local phone	High	Med