Just to clarify, you can go from either Santiago -or- Lima (Peru) to Easter Island. (But yes, only on LAN and it won't be cheap.)

Actually, this is one of the world's most isolated islands so bear in mind that *nothing* about this venture will be cheap..

That said, it's fantastic! Stay a few days and definitely rent a car (this island is teeny tiny and easily navigable).

Flights depart from Santiago only with LAN Airlines.

On the island has to buy tickets for the Rapa Nui National Park to visit the Moai Quarry and Orongo, price USD 55.

The most beautiful places are Orongo, Rano Kau Volcano, Vaihu, Tahai, Ahu Tongariki, Vaihu, Vinapu, Anakena, Ovahe Beach, Ma'unga Terevaka ...

The best activities trekking, scuba, snorkeling, tradicional show, riding, boating, coast fishing, polynesian dance taller...

If you need more information you can contact me.

Plane is the only optiona dn there are only planes from Chile to Easter Island.

From what i know then LAN Chile from Santiago is the only airline servicing the route and it's not cheap tickets.

Just so that you are warned.

Easter Island is very far off the coast and it would take several days to go there by boat, so you have no regular ferry service to the island.

There's also limited flights to/from Easter Island from Pape'ete if you're feeling super adventurous. :) 

I just booked a LAN flight from Santiago to Hanga Roa a couple of weeks ago.   It will cost you about $600 return for the 5-hour trip.  As has been mentioned, it's one of the most isolated places on earth, which can make it a very expensive destination.

If you need to cut costs, and don't mind dormitory accommodation, you can stay at the Kona Tau Hostelling International in Hanga Roa for about $30 each per night.