If you want to find something a little more out of the box, fun and authenitcly hawaiian most people down the shopping strip on Waikiki. I would recommend the International Market Place in Waikiki
. This is like a little bazaar of local hawaiian shops. Lots of high-quality low-costs gifts can be foud here. Some good ideas are koa wood products (like large bowls and cuttng boards) etc.
Its a great place to shop around. One shop there does hawaiian music boxes and they do custom photograph boxes as well (think wedding photos). I have these as a party favor to family during my sons reception dinner.