A flight from Palma de Mallorca Son Sant Joan to Ibiza, which has 0 stops, is S$ 167 which is the least expensive round-trip domestic flight that Wasaya offers. For a one-way domestic Wasaya flight, the cheapest route is Ibiza to Palma de Mallorca Son Sant Joan (0 stops) for S$ 74.
Wasaya does not have flights from Singapore Changi at the moment. There are scheduled flights with Wasaya out of Menorca/Mahon though (if you don’t mind flying from this airport). Flying with Ryanair is recommended if you still want to fly from Singapore Changi.