This is the cheapest way of getting from the airport to the city centre or seaside resort. They are generally found at the arrivals area's exits. They can transfer between 20 and 60 passengers and generally circulate every 10-20 minutes. Keep in mind that more and more hotels are also offering this service to their guests upon arrival, (either for free or for a charge).
Also interesting to note is that there are now shuttles that operate like collective taxis. You register the night before and the shuttle comes to pick you up at the specified time. A shuttle is an airport transfer service for which the cost is split between the users. Departure times are determined in relation to the flight time of each passenger.
For a more flexible option, group shuttles pick you up at home for less than the price of the metro or the train. This service allows you to take advantage of the comfort of a vehicle, while saving time and money.