Every journey is quoted on its own rather than sold from a price list, so the figure you receive is for your booking. These are the things that move it. Nothing is charged until you accept the quote. Tolls, where they apply, are either included in it or shown in it as an additional charge, and heavy traffic does not change the quoted price.
Which terminal, and which airport
The pickup point comes from the airport code and terminal on your ticket. Terminal 2 is a separate pickup on the far side of the airfield, and DWC is a different airport in Jebel Ali, so the wrong code means the wrong kerb.
How far down the coast
Addresses run from Deira, minutes from the terminals, to Jebel Ali, 40 km or more away, and the quote is worked out for yours. Salik toll gates sit on several routes south, including the Al Garhoud and Al Maktoum bridges and Sheikh Zayed Road.
The hour and the date
A late-night landing, a UAE public holiday or a booking made at short notice can each add a charge, named in the quote before you pay. The holidays include the two Eids, whose dates follow the moon sighting, and National Day on 2 and 3 December.
Your party and its luggage
The vehicle is chosen on passengers and bags, in whichever class you book: a sedan takes about 1 to 3 passengers with 2 to 3 bags, and a van about 5 to 7 passengers with 6 to 8. Declare golf bags, pushchairs and other bulky items when you book.