There are solid discounts, but the travel window is tight (May 24 to June 22), blackout dates (May 26-31), and other restrictions. Here's the fine print.
The prices, however, while not off-the-hook, are pretty good. Some sample one-way fares from Boston:
$39 to Baltimore; $44 to Washington, DC (Dulles); $49 to Pittsburgh, New York City (JFK), Newark, N.J.; $54 to Richmond, Va., Washington, DC (Reagan); $64 to Raleigh-Durham; $79 to Charlotte; $89 to Jacksonville; $92 to Orlando; $99* to Tampa, Chicago, (O'Hare), Bermuda, West Palm Beach; $109 to New Orleans; $119 to Cancun, Mexico, Denver; $129 to Phoenix; $139* to San Jose, Calif.; $149* to San Francisco, Long Beach, or Los Angeles; $159 to Portland, Ore., or San Diego