Samsung Galaxy S4 Mini, just £7.99 a month on a 2 year o2 contract. No upfront cost, original monthly payment of £18! Is a refurb, but can't complain when it's such a low monthly cost.
Link is for the pink version, other colours are available, although I'm unsure whether they are available at the same price.
You get unlimited texts, 500 mins and 500MB of data. Obviously not the best amount of data, but you're getting a great phone for such a low price.
Standard cost £18.00 p/m.
Save over £240 cashback by redemption