Check-in for Spirit is on the B-side of the terminal. Cheapest transportation option depends on a few things, particularly how many people are traveling. Please see https://orlandoairports.net/parking-transportation/ for the different options.
Spirit is very affordable however check Frontier and Southwest depending on where your coming from. Daytona International is completely separate from OIA
U also have locals who are renting their cars if u can't find any rental. There's an app for it
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