The bill for our mobile phone services somehow piled up to $85 this month. With Emma in the hospital not once but twice, I was sending text messages to family (and eventually coworkers) to the point that I had more than thirty messages about my monthly allotment. That added up to $9. Then Mari took a 28 minute call on her phone that was all above her allotment of minutes. She wound up paying almost $20 in minutes, not knowing that she was paying for incoming calls (Canada is the only country I know of where you pay for incoming calls).
So I've done something about it. I found a cheap operator that will give me more minutes and text messages for a flat $20 a month, a non-branded player I'd never heard of. They use the same network we're already on, so that'll be fine for my limited needs.
For Mari, I've actually "upgraded" her account to a smart-phone system that will allow her to send text messages in Japanese. It'll also have a data plan, so she can find out where the buses are and use some of the great language/translation "apps" that exist these days. The upgrade won't cost us more, and again comes with more minutes and messages.
Keeping on top of this stuff is boring, but it'll save us $25 a month and the aggravation of having to watch the billing.