In reply to Voltemands:
I bought a Samsung Galaxy Y at Carphone Warehouse last year for £50 as a Vodafone upgrade and it has been brilliant.
It's on a Voda PAYG with a Text and Web Freebie.
I use it for all the mountain and MR stuff. That includes mapping and locaing apps and tethering wirelessly to a laptop (which has worked in various coverage types with speeds from 9kb to several Mb).
The built-in email app is good. I use Opera Mobile when in 3G or HSPDA coverage and Opera Mini when in GPRS or EDGE coverage: good results. WiFi works well, as does Bluetooth.
Most heavy usage facilities are turned off or turned down to conserve battery life. Without long voice calls, GPS, tethering or lots of Opera Mobile browsing, the battery makes it through the second day. Usual stupidphone rubbish.