You can get a direct roundtrip flight from Duluth to the Phoenix area for bare-bones prices if you mind your mouse clicks -- and for less yet if you go to Duluth International Airport and book your flight through a ticket agent.
Allegiant Air's flights have a la carte upgrades, some that are the automatic setting for online booking, which can increase the fare by more than $100. It's up to you, the passenger, to determine whether priority boarding is worth $4.99 a flight or if you will pay a total of $30 to select your seat.
Note: Remember that you are booking a flight to Mesa, Ariz., which is about 45 miles from downtown Phoenix. This is important when it comes to car and hotel reservations, if you choose to deviate from Allegiant Air's travel packages.
Here are things to watch for if you are looking on the Allegiant website for the least expensive, no-car, no-hotel option: Allegiant First Priority is a service to avoid lines at the screening checkpoints for $4.99 each way. You have to manually add this service. You will see a map of the inside of the plane, as well as your name and seat number and a charge of $14.99. You can eliminate this charge by clicking "Change" and then "Remove." Open seating means that you will board in the last wave and have your choice from the remaining seats, like general admission seating. Plenty of travelers on recent flights went this route. You will get a seat.
Also note: If you have opted to pick your seat and are late to the boarding gate, you will end up forfeiting your hand-picked seat and boarding with the general admission crowd.Checking a bag? That is a $49.98 charge and the default pick when booking a flight. You can avoid this by sticking to carry-on luggage. You have to click to remove that option.This one is tricky: "I want the flexibility to change my itinerary with zero change fee." The box is checked, by default. Uncheck it to save $23.You won't get a complimentary Coke. It will be $2 if purchased from a flight attendant, the same as snack-sized cookies and pretzels. Beer and wine run about $7. Going to the Duluth International Airport and booking at the Allegiant Air ticket counter knocks off a convenience fee that comes with booking online, though agents don't keep regular hours. The best bet is to stop by when an Allegiant Air flight is arriving at the airport.