Where is an inexpensive, safe neighborhood in Oahu for four 21 year olds to live from Mainland

We are four girls around the age of 21 who are planning on making the move to Oahu in a years time. We are moving from Kansas City, Kansas and we know that we need to anticipate a higher cost of living. What neighborhoods in Oahu are inexpensive while still being safe and with young collegiate people around to make friends? We are open to being away from the heart of Honolulu. We need a furnished place whether it be an apartment, duplex, or small home.