E2SAVE (one of the more reliable cashback dealers, part of CPW) are doing a new Nokia 6300 on O2 which gives 800 cross network anytime minutes and 500 texts. 12 month contract paying £45 a month with redemptions at months 4, 6, 8, 10 and 12 totalling £495 cashback, meaning you pay £45 over the contract or £3.75 a month.
Its possible to get quidco as well, £36.50 for completed contract so you could get this deal for £8.50 or 71p a month.
My bad! Its a clearance, not a 'new' phone.