"I got New York to Puerto Rico, round trip, for $77," said an elated passenger.

Delta Air Lines is giving some air travelers a post-Christmas treat.

Yesterday, people booking Delta flights could get them at ultra-low prices, some down to 20 bucks for a round trip.

Jason Herbert tells NBC's "Today" show he got a round trip deal from New York to Vegas.

"I was in complete shock.  I was like oh my God.  I was like, wow, for me to get in for 81 bucks?  Merry Christmas to me," Herbert said.

The airline says it will honor the "mistake fares."