Would it better for me to buy my ticket at the airport on the day of my flight taking off or a few days before my flight flies into the sky?

I need and want to know would it better for me to buy my ticket at the airport on the day of my flight taking off or a few days before my flight flies into the sky? To be more specific, is it better for someone in Austin, Texas who wants to have a 1 way window seat flight to Denver, Colorado to buy the plane ticket at the airport on the day of their flight or a few days before their flight to Denver takes off? I need to learn these things because i've never traveled by flight before in my life? Please help me!

Added (1). BQ: Can a person pay for a plane ticket either with a debit card or cash up front?

You may not get a ticket when you want it if you wait. And you are unlikely to get the seat you want. Pick an airline. Recommended by someone you trust, call them and ask for help. As soon as possible.

Airlines try to sell a plane out before it is due to fly. Thus, once you get to the airport in the last hour or two before the flight, there may be NO seats left on it at all.

And, if you want a firm booking with a choice of seats, booking as early as possible is the only way to get that. Plus last minute ticket prices at the gate are the highest charged.

It's better to buy a ticket at least several weeks before your fly - buying a few days before or even the day of is going to result in a more expensive fare, if there are even any tickets available at that point. You have less chance of getting a window seat the longer you wait as well.

You can use a debit card to purchase a ticket.

It would be better and cheaper to buy your ticket well in advance of when you want to fly.

You will not get any seat on an airline if you try
to buy a ticket on the day of your flight
airline tickets are always booked well in advance

You would be lucky if you get a flight the same day. Many airports don't even accept cash. So you would have to pay by credit/debit card. Go on your airline of choice and just pay for a ticket.

I don't think you can purchase tickets at the airport any more.
You will find it cheaper to purchase your tickets as far in advance of your flight as possible.
Tickets purchased six months prior to the flight can be a lot cheaper than tickets purchased closer to the flight.
AND you get Seat Selection with advance purchase.

I've heard that sometimes a "last-minute" booking is cheaper, but if you do so you run the risk that your flight is full already.

Tickets usually get more expensive the closer you get to departure.
Some airlines don't accept cash at airports anymore.
Also, trying to buy a ticket at the airport is rude to other passengers. Most airlines only have a few agents working the counter now and their main job is to assist passengers with check in. If you walk up trying to buy a ticket, you are going to delay passengers waiting on line trying to check in for their flight. Some airlines might allow you to buy a ticket from a kiosk at the airport.

Tickets go up in price the closer you get to departure and purchasing a ticket day of will get you flagged as AAA and subject to closer scrutiny at Security - that is, if you can even purchase a ticket as flight fly full these days. Forget trying to get a window or aisle seat, too