Quito airport to Galapagos
To go effectively from the Quito airport to Galapagos you will need to catch a flight either with TAME, AERGAL or LAN. Flights for foreigners are usually around $450 round trip and the passage takes about 2 hours.
Sometimes there are specials for Ecuadorian citizens and residents that are announced in the local paper (for sometimes as low as $150 round trip!)
It is possible to buy the ticket a few hours before flying from the airport ticket point.