I use Ting, which rides on Sprint's network. With my usage I pay $22.50 a month after tax. If I turn the data on to check something (rarely, I am pretty much always on wifi), my bill is about $25.50.
I got a refurb'ed Iphone 4 from them for $91. My bank and a couple of other apps don't work with a 4 anymore, due to IOS upgrades, but they want $191 for a IPhone 5, which I don't need at this point.
When my business puts me in a position where I need the 5, I will get it, but hopefully it is less expensive then. I don't see the value add, as if I am home I can check the bank on the Ipad on wifi or the laptop. I don't need to check my bank on the go, as I know how much is there and it doesn't change by the hour.
And I am a millennial who thinks all the smartphone crap is a huge drain on people's budgets. No cable, no data, $35 internet, all good.