Alaska Airlines' winter sale has flights going for as low as $39

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• Alaska Airlines has launched a winter sale, with fares as low as $39.
• The deal is only for a limited time, and more popular routes are more expensive.
• JetBlue is also offering a winter promotion right now with dirt cheap tickets.

Alaska Airlines' winter flight sale has flights marked down as low as $39 through Thursday, January 10.

Cheap seats on the Seattle-based carrier are available in both its traditional "Main" fare economy cabin as well as in its newly launched "Saver" fare option, which is a less restrictive form of the basic-economy product offered by American, Delta, and United.

Some slick deals spotted by Business Insider include San Francisco to Orange County for $39; Orange County to Puerto Vallarta, Mexico for $109; Austin to Portland for $99; and New York to Los Angeles for $129.

As always, there is some fine print. Tickets must be purchased for travel between January 29 and March 13, and travel booked at least three weeks before departure.

Alaska Airlines ran a similar deal in December.

Alaska's Saver fare and other basic economy tickets are discount fare classes within an airline's economy cabin. As a result, the in-flight service and experience will be the same for the Saver fare as it will be for someone who purchased a pricier Main-fare ticket. This means passengers who go the Saver route will sit in the same seats and enjoy the same in-flight perks and amenities as everyone else in coach.

Saver-fare tickets are not changeable or cancelable, and they will not be eligible for upgrades. Those traveling on Saver-fare tickets will also board last. And while you will be able to preselect your seat, it will have to be at the back of the plane.

Ben Zhang contributed to this report.