A top travel hack is always adding a bag to your booking when you initially purchase a ticket! It is almost always cheaper to do this than paying for checked luggage at the airport. Even if you arrive at the airport and forget, an experienced traveler's trick is to go on your phone, open the browser or app for your airline, and pay for a checked bag there. It's a great way to save money.
Now you don't have to worry about the crazy prices at the airport and be worried about the long checked baggage lines!