Mobile Outlet are doing a fantastic offer - 12 Month Free Line Rental on a 12 month contract (Vodafone 200 minute contract) and the V3i is absolutely free. This works via Cashback.
Also, if you do this via QuidCo you'll earn yourself 30 quid (I think?)!
You can read reviews on Mobile Outlet: HERE
Edit// Would a mod please edit that? :P Screwed up the link.