Let KAYAK do the searching
Based on KAYAK hotel searches, the most popular destination is Christchurch (42% of total searches to South Island). The next most popular destinations are Queenstown (39%) and Dunedin (12%). Searches for hotels in Wanaka (6%) are also popular.
KAYAK users have found double rooms in South Island for as cheap as $40 (Queenstown) in the last 3 days. The average price is $286.