Today I decided to start with Ting; since they don't support my iPhone version, I got their cheapest, stupidest phone (88$ brand new) and will continue using my iPhone at work and home where I have constant WiFi for streaming music and email and all the other crap I shouldn't be paying for. The mobile devices thread worked wonders to get me mad about services I don't use but still pay for.
In July I jumped from AT&T (73$ / month) to TMobile (58$ / month) for the same services, and Ting says I'll average 17$ with their services - probably less, since the cell phone doesn't sound as text or data friendly anyway. So today I ordered my Ting stuff and by Christmas I'll have gifted myself an extra 40$ a month. Bam!