Apart of interesting deal to America when departing from UK we posted today (Roundtrip flights to Boston already for Ł295) you may also consider another great solution how to visit USA with very low budget! Based on service of US Airways and their partners Finnair/British Airways you may consider to book roundtrip as well as open-jaw flights already for Ł287/€358. The cheapest flights are available when departing either from Brussels or Copenhagen. Your return flight has to be then back to Germany or London.
US Airways promotional offer allows to book these cheap flights to New York or Los Angeles in travel period between 1st of Nocember till 16th of December 2014 and from 7th of January till 28th of February 2015. To book the lowest fare available you have to look for flights departing till December 2014. This is based on date of your outbound flight from Europe to USA.
The easiest way we recommend is to check your connection possibilities is through Skyscanner.
Booking sample of cheap flights to USA (New York and Los Angeles) for just Ł287 below. In this case you would be departing from Copenhagen to New York on 1st of December. Your return flight from USA back to London would take place on 9th of December 2014.