Saw this deal on buymobilephones.net
Nokia 2730 Classic on T-Mobile 18 month contract
Contract includes: 600 cross-network mins + 500 texts + Unlimited data all for £30.00 a month
However, all 18 months line rental is free by redemption, so you can get the phone and contract for free for 18 months as long as you send your bills in within the set time periods.
Therefore, the EFFECTIVE COST of the rental is completely free! :)