WOW air is an european low-cost airline just like Spirit Airline. You have to pay for any carry-on that is heavier than 5kg, check bags, and pre-selecting seats.
Currently and for very limited time, they have flights from March-June of next year for $252-285 from Boston. Baltimore flights start from June 2015. Act quick! This will not last. See samples below. And you can even do 2 countries for even cheaper or just go to Iceland even cheaper than my example below! scroll down to see how.
Looking at my example above, let’s say you want to go to Iceland. In my example, it shows $284.90. If you are able to fly with only a carry-on, purchase a ticket to London instead of Iceland. BOS-London is $99 with a layover in Iceland while a direct flight from BOS-Iceland is $129. Once you get to Iceland, just leave the airport and enjoy Iceland. Make sure you buy a separate one-way ticket back to Boston. With this method you can save $30.
Using the same method, you can go to Iceland, purchase inter-european flight/train to either London or Copenhagen and book another one-way back to your hometown!