Icelandair has round-trip flights from Chicago (ORD) to Dublin (DUB) for $361-$404 with a connection. Flights April to May.
Some small OTAs on Skyscanner have this for as low as $361; which is cheaper than the airline. If you plan on booking there, beware of any site that charges a fee to cancel a ticket within the 24-hour “free” period. Use unknown booking sites at your own risk.
This is a small subset of the European Fares on sale. We covered all of them in our European Airfare post from over a week ago (linked).











