The red 1.2 Mini One three-door hatchback has been donated by Barretts of Canterbury.
The car will go on show at the shopping centre in St Wilfrids Way on April 17 and April 18 when visitors can buy a raffle ticket for the draw.
The charity has helped thousands of people and saved many lives after attending more than 25,000 call-outs over the last quarter of a century.
Air Ambulance Head of Promotions Katie Eeles said: “The service we provide today would simply not be possible without the kind support of the public.
“The need for our life-saving service will never go away, and your support will help to ensure that we can continue helping patients who need us for many years to come.”
Tickets for the Win a Mini raffle cost £5 each.
The draw will take place on December 2015, making it a perfect Christmas present for one lucky winner.