Santiago has an excellent public transportation system, so you won’t really have any issues getting around in the city. You can also get from the airport to Santiago reasonably quickly by using sanctioned airport taxis and transfers.
If you’re traveling with a group of people, or if you meet friends at the airport who are going in the same direction as you are, you can always lower the cost by sharing a taxi. One caveat; always make sure that you take clearly marked airport taxis.
Sometimes, taxis in Santiago will refuse to run the meter, and you could find yourself paying way more than you bargained for. Airport taxis are regulated, and they always use the meter and know where they’re going. So it’s a safer, easier, and headache-free option, especially at night.