Let KAYAK do the searching
Based on KAYAK hotel searches, the most popular destination is Padang (67% of total searches to Sumatra). The next most popular destinations are Medan (11%) and Dumai (11%). Searches for hotels in Parapat (11%) are also popular.
KAYAK users have found double rooms in Sumatra for as cheap as $56 (Medan) in the last 3 days. The average price is $58.