mine is due to run out and, never having had a phone before this, i need to know what the best way of going about getting a decent deal?

currently with vodafone paying ~£20 for 250 texts & about 100 minutes calls, but with the stop the clock thing so that any calls over 3 minutes only cost you 3 minutes so i never go anywhere near using all that.

Vodafone's current deals look shit, so any suggestions would be good.