WOW Air has some amazing prices if you live around Boston and are planning a trip to Iceland (or to the rest of Europe from there). JUST $99. You can fly from Boston to Reykjavik for less than $100 during the months of April, May and June 2015.
Fares for the return leg are a bit more expensive at $164.39, which is still a great price for a transatlantic flight. So the total cost for a round trip will be $263.39.