Let KAYAK do the searching
Based on KAYAK hotel searches, the most popular destination is Queenstown (65% of total searches to South Island). The next most popular destinations are Christchurch (25%) and Wanaka (5%). Searches for hotels in Te Anau (4%) are also popular.
KAYAK users have found double rooms in South Island for as cheap as $17 (Kaikoura) in the last 3 days. The average price is $285.