You’ll have to watch the nickle and dime but cheap flights from many US cities to Europe from only $99 one-way.
Also works in reverse (from about €124 one-way).

DEPART:
Pittsburgh, Boston,San Francisco,Chicago,Washington DC,Miami,New York,Detroit,St. Louis,Cleveland,Cincinnati,Los Angeles but check schedules as your airport choice could vary. The $99 lowest fare dates are very limited but some are out there.

Fly to (depending on airports used):
Brussels, Belgium
Reykjavik, Iceland
Copenhagen, Denmark
Dublin, Ireland
Milan, Italy
London, UK
Frankfurt/Berlin, Germany
Tel Aviv, Israel

Book at: Wow Air
Availability from September 2017 to August 2018

Save the comments about how bad low cost carriers are, etc. Wow is no free lunch or joyride but it can get you to Europe for $99 plus add on fees. It doesn’t get much cheaper for that. Think Greyhound not Emirates First people.