[pulledpork]

Do they at least ping you to let you know you're out of funds? In an ideal world I'd hope they'd extend you some credit.

[munger]

It's easy to setup correctly. It lets you set a rule like "buy me X credits when I get below Y credits"

I think ours is something like buy me 20 credits when we get below 5.

Also you can install their iphone app and use push notifications for free instead of or in addition to SMS.