My monthly usage will be $15:
$6 for my device
$3 for less than 100 SMS
$3 for less than 100 minutes
$3 for less than 100 MB
After taxes, fees, surchages I'm guess total will be $20-$22. Our bill for the both of us with AT&T, after 25% discount applied, was $118/month. She hasn't switched yet but will soon. Service works great everywhere I usedit.
In our city, AT&T sucks and I had to have a Microcell plugged (something I paid $300 a couple years ago, ugh). After she switches out we'll even save on electricity for that thing.
I always hated talking on the phone and just skype with family and IM instead of texting, phone is always connected to Wifi somewhere and I have mobile data turned off on my phone and enable it when I need to use google maps or check the public transit app, etc.
I believe there is a referral thread somewhere around here if anyone was wanting to switch, be sure to check that out. I ended up getting $25 credit from a referral from a friend.