Let KAYAK do the searching
Based on KAYAK hotel searches, the most popular destination is San Sebastian (50% of total searches to Atlantic Coast). The next most popular destinations are Bilbao (34%) and Vigo (8%). Searches for hotels in A Coruña (7%) are also popular.
KAYAK users have found double rooms in Atlantic Coast for as cheap as $24 (Santiago de Compostela) in the last 3 days. The average price is $250.