unlike budget airlines where closer to the flight date, the price go,s up.With usa flights there are times that it is cheaper.The main one for sales is xmas/new year,but as others have said you have to keep checking.Best thing to do is have a realistic price in mind and if it drops book it(no wayne you carn`t have a £1 flight) that way you will not miss out if it gos`s.
They days we have had £99 and £199 virgin flights have long gone, oh happy days
Then again were going next aug no matter what after not going this year my price range will be £600-£650 indirect
Paul