The price depends upon when you wish to travel. To give you some indication of one-way fares, they can be as low as £80, so long as you don't mind flying via a few cities enroute (I certainly wouldn't mind! In fact, the more the better!). Visit travelocity.co.uk for info. You should be able to get a return ticket for under $250 - which might involve, if you so wish, travelling via, say, a total of 6 cities.
"Everyone writing for the Telegraph knows that the way to grab eyeballs is with Ryanair and/or sex."