T-Mobile currently offers its Simple Choice customers free global roaming. When you roam, though, you're locked to slower networks unless you want to pay for an upgrade. During July and August, customers can take advantage of 4G LTE speeds where available without having to pay for faster data.

"Customers get the highest available data speeds wherever they travel across the continent," T-Mobile said, reiterating that texts are free and calls are $0.20 per minute. In celebration of the deal, T-mobile said it's also offering customers a free hour of Gogo in-flight Wi-Fi on flights equipped with the technology. That deal kicks off beginning tomorrow, June 24, and runs through Sunday, June 26 at 11:00 p.m. EST. The deal is open to all travelers, T-Mobile said, noting that its customers always get a free hour of Wi-Fi in the air.

If you're not on T-Mobile, grab an unlocked cell phone and a SIM card when you travel abroad. It can be inconvenient, but you'll save on roaming fees, that's for sure.