Jessie Purton won the frugal travelers’ lottery.

A bit of luck, some quick thinking and lots of flexibility landed her an amazing travel deal: a four-night Carnival cruise to Mexico plus two nights in a Miami hotel for just $275.

Purton, 30, found the cruise online last January, shortly after the Costa Concordia — owned by Carnival — ran aground off the coast of Italy. She and six friends booked the deal using a BlackBerry.

“They were giving everything away,” said Purton.

Savvy travelers can find some incredible travel sales but they need to have fluid schedules and willingness to vacation at off-peak times. An understanding boss is helpful, too.

Purton is part of a small group of travelers who pick their vacations based not so much on destination, but cost. That could mean sitting on a tropical beach, strolling down the Las Vegas strip or sailing through the Caribbean — as long as the price is right. They’re the types of people who always have a suitcase always packed — just in case.

“If I could be anywhere in the world, I would be on an airplane. I love traveling,” Purton said. “I come from a family of pilots. I guess it’s in our blood to travel a lot.”

Two years ago, Purton found a last-second vacation on the Monday after Thanksgiving — dubbed Cyber Monday for online shopping specials. JetBlue was practically giving away Las Vegas vacation packages.

She and a friend booked roundtrip tickets from New York to Vegas and two nights at the MGM Grand Hotel & Casino for $140.80 each, including all taxes and fees.

Sure, they had to leave on a Tuesday and come back on a Thursday, but the price made it worthwhile.

“That was the best deal I had ever heard of,” she said. “Everyone I know wants me to email them when I see the next one like this.”

Sales like that typically last a few hours and require flying on off-peak days. But Purton, who works for a fashion tech startup, is lucky enough to have a flexible boss.

“I’m a single gal. I don’t have a family to take care of,” she added.

Here are the best ways to find insane deals:

• Download mobile apps, bookmark pages, create online profiles and add credit card information. That way, when a deal comes along, you can book it from anywhere with minimal hassle. By the time you get to a computer, it might be gone.

• Twitter and Facebook are your friends. Sometimes airlines, hotels and cruise lines will post their deals on social media. More often, you will hear about them from industry watchers or friends.

• Sign up for text alerts. Travel blogs like Deals We Like — http://boardingarea.com/blogs/dealswelike/ — will send you a text when there is an amazing special with a short shelf life.

• Question travel newsletters. By the time a travel company emails you about a “sale,” most of the spots are gone. Also, sometimes those deals aren’t any cheaper than what is normally offered. Like any savvy shopper, know what typical prices are so you’ll know when the price has truly gone down.

• Search for last-minute weekend fares. Each Tuesday, airlines email offers for that coming weekend or the following one to fliers who have signed up online for deal alerts. Travelers have to depart late Friday night or anytime Saturday and come back Monday or Tuesday. But at least the trips don’t gobble up any of those precious vacation days.