Think back to the 2010s. Did you fly Spirit Airlines during that time? Did you book your ticket through a third-party online travel agency like Expedia or Travelocity? If so, you may be eligible for some money back.

As part of the settlement agreement of a class-action lawsuit, Spirit will pay up to $8.25 million to help customers recover fees paid for carry-on baggage. Certain passengers who booked tickets from 2011 to 2017 may be eligible for some cash.

After the agreement received preliminary approval from a federal judge in September, customers can now submit a claim online to opt into the lawsuit, according to attorneys for the plaintiffs. If you think you may be eligible, you should act fact. The deadline to submit a claim is Jan. 10.

Here’s what you should know if you think you might be one of the affected customers.

Why was Spirit Airlines sued?

The settlement deal involving Spirit Airlines stems from a class-action lawsuit filed Aug. 31, 2017, on behalf of passengers who booked tickets on Spirit through online travel agencies.

The lawsuit accused the airline of “bait-and-switch” tactics. It said Spirit lured people with discounted fares “designed to confuse, trick and trap customers." Specifically, the lawsuit said Spirit essentially charged people surprise carry-on bag fees they wouldn’t have known about as first-time Spirit flyers.

“Spirit makes up whatever discount it purports to give consumers in fraudulent and unwarranted charges,” the lawsuit said, accusing the airline of misleading consumers “into believing they are purchasing low airfare.”

As regular budget airline customers know, the ticket price is only part of what you ultimately end up paying. As you go through the booking process, fees are added for things such as seat selection and carry-on bags — a tactic known as "drip pricing."

Who would be eligible?

Six years of legal maneuvering preceded a settlement agreement on Aug. 23. Court documents reviewed by NerdWallet show Spirit has agreed to pay up to $8.25 million to customers.

According to the documents (pending a judge’s final approval), you may be eligible if you purchased a Spirit ticket through one of six online travel agencies from Aug. 31, 2011, to May 3, 2017. Those agencies are:

Expedia.

Travelocity.

Kiwi.

CheapOair.

Cheap Tickets.

Bookit.

Passengers who can establish that they were affected may be eligible for payments of up to 75% of the carry-on baggage fees paid — although the exact percentage will depend on how many people make claims.

The Angeion Group, a settlement administration company, would serve as administrators according to court records. The company plans to alert eligible customers via e-mail addresses from Spirit, then it will try mail and mass social media campaigns.

That outreach should contain information on how to apply as a potential claimant on a website the company plans to set up.

(Top photo courtesy of Spirit Airlines)