Not a lot. You could manage a Mars Bar, perhaps a Newspaper, or even five packs of Tesco Value Chicken Noodles. Or you could get one of the seven iPhone games that are currently in the I-play Summer sale.
Running from today through to June 14th, each of the following I-play games on the iPhone will be available for a mere 59p. Snap them up quick for some mobile gaming fun.
PDC World Darts Championship
National Geographic Plant It Green
Hip Hop All Star