Another interesting suggestion based on service of Icelandair would be multiu-city flights from UK to Iceland and Canada (Halifax) already for £252. (€318). In this case you may consider to fly from London, Manchester but also Birmingham or Glasgow. Flights are available from September 2016 meaning you may visit both destinations right after main season ends..
Please note that Icleandair offers free, up to 177 hours, stop-over in Iceland. If interested in this deal you may find the cheapest flights in travel period between 1st of September till 27th of October 2016. (Latest day of your return flight back to UK).
If you consider to book this deal you may find some cheap connection flights to one of these cities from your hometown using service of Skyscanner. This tool helps you quickly to find out which low-cost airline is connecting from your city. To check some cheap accommodation you may compare the hotels in Reykjavik and Halifax via various booking agents. Consider to use Hotels.com, Hotelopia or Venere as they are offering promo codes to further discount your accommodation.
Booking sample of cheap multi-city flights from UK to Iceland and Canada (Halifax) £252! In this case you would fly from London to Reykajvik on 3rd of September. After that you would depart from Iceland to Halifax in Canada on 10th of September. Finally you would return from North America back to Europe on 17th of September 2016.