Get flight miles. Search for the 15k each way ticket.
Skip the hotel. Hotels are up to $1000 usd per night in prime areas. Get a hostel for a few nights.
Get an apartment near Playa den Bossa in IBIZA TOWN (not san antony) within walking distance to everything. A luxury 2 bedroom 2 bath apt is $700 per month. Split it with 3/4 friends and exchange free nights in the living room in exchange for VIP passes etc. Get the cheapest handy/cell phone for $10.
Walk to the nude and topless beaches. Make friends and enjoy!