Some travelers were really lucky Thursday night after United Airlines mistakenly gave away tickets for free or very low cost.

Passengers reported buying tickets for $5 to $10, or even free, before the company shut down the bookings site and phone centers.

Airline spokesperson said the company accidentally filed some fares for $0, with airport charges adding just a small cost for the passengers.

Fare mistakes like this one have have happened before, often when an airline dropped a digit when entering the numbers into the computer system.

That's what the spokesman said may have happened in this case, saying it was a mistake due to an error in filing the costs, not a problem with the website itself.

United said it is not sure how many tickets were sold at the severely slashed prices.

Meanwhile, United said Friday afternoon that it will honor the bargain prices.

In 2008, United accidentally dropped a fuel surcharge that could have run as high as $130 a ticket.  It honored the tickets without the surcharge.

Associated Press contributed to this report.