Get an iPhone, get a GoPhone SIM, put the SIM in, turn of "Cellular Data" in the Settings app. I do this for my sister, I pay $9.99 for text and 10¢ per minute. The average month costs around $13.
just FYI, if you leave the data on you can send MMS texts without being charged for data. the APN on the iphone is not setup correctly for gophone so it won't charge you for the data.