so another question, how much ‘data’ does soemthing like cyclemeter use? surely its just GPS, which is free?
Normal GPS doesn’t use any data – it doesn’t download or upload anything from t’internet, it just listens to radio broadcasts from satellites.
But beware of apps that stream maps etc from the internet as you go – that’ll use tons of data and will really hurt.
You don’t say what phone you are on, but FWIW I use the “MotionX GPS” app on the iPhone*.
It lets you pre-load maps for a very large area while you are still at home on wi-fi, so you don’t need to hit any data while you are out and about – and it uses map data from OpenCycleMap so it has important stuff like pubs marked.
(*other smartphones are available)