Let KAYAK do the searching
Based on KAYAK hotel searches, the most popular destination is Castro (57% of total searches to Lago d'Iseo). The next most popular destinations are Sulzano (29%) and Riva di Solto (13%). Searches for hotels in Sarnico (1%) are also popular.
KAYAK users have found double rooms in Lago d'Iseo for as cheap as €90 (Iseo) in the last 3 days. The average price is €160.