If you have unlimited data plans with AT&T you may qualify for the AutoPay and paperless billing credit. For single line it'll be $10 credit per month and multiple lines receive a $20 credit/month. All mode of payments used for AutoPay such as credit cards, checking and debit cards are eligible to get the credit. It'll take 1-2 billing cycle to see the credit after enrollment. Higher cost of unlimited plans can be reduced with this credit. It's worth exploring the unlimited plans since it also comes with many other perks like getting 30+ channels of live TV. 

T-Mobile One wireless plan includes Texting & data abroad. As part of the plan you can text and use the data in 140+ countries and destinations with no additional roaming charges. Another good thing is, T-Mobile includes all the taxes & fees in the plan price.

You might be eligible for savings for your qualified AT&T wireless service through your employer, school, or other association. You can easily check this in AT&T web site instantly by submitting your work or school email address. If you are eligible, it'll show in your plan as something similar to '20% AT&T Signature Program discount included'.  It's a huge saving every month so don't let it go.