Jetblue Airways have round trip airfares travelling to and from Minneapolis (MSP) and Boston (BOS) for $ 108, nonstop.

Travel Availability:
Departs BOS: July 10-12, 17-20, 24-25; Aug 14-15, 21-22, 24, 27-29
Departs MSP: July 11, 17, 24; Aug 22, 26, 28, 29

Use dates and book it on your favorite and reputable OTA such as Expedia [expedia.com], Hotwire [hotwire.com], Travelocity [travelocity.com] or JetBlue [jetblue.com] directly. Bundling hotel with airfare will save money.