"A University of Leicester space scientist has worked out that sending texts via mobile phones works out to be far more expensive than downloading data from the Hubble Space Telescope. Dr Nigel Bannister's calculations were used for the UK's Channel 4 Dispatches programme "The Mobile Phone Rip-Off". He worked out the cost of obtaining a megabyte of data from Hubble - and compared that with the 5p cost of sending a text. He said: "The bottom line is texting is at least 4 times more expensive than transmitting data from Hubble, and is likely to be substantially more than that."
I guess I've never really noticed the cost of texting too much because I've pretty much always had T-Mobile's unlimited texting plan. If you aren't on an unlimited plan though, it is a bit scary thinking it is cheaper to send data from space than it is to your neighbor across down.