Cheap pre-pay phone for GPRS?

I want to buy a cheap pre-pay mobile phone for the sole use of
connecting my new TomTom GPS system to the internet, so it can pick up
traffic data.

Therefore the only features the phone has to support is GPRS and
Bluetooth. I was looking at Orange because they seem to have sensible
data rates.

Any suggestions of where to get a cheap handset on Orange? Or
suggestions welcome as to why I should pick another network...

Bonus points if the phone is one of the ones mentioned in the
"compatibility" list on this page:
http://www.tomtom.com/products/featu...=74&Language=1

Ta!