OP, you did not specify what Island you are going to.... Hawaii is not a single piece of land.
And Staying for $90-150 is totally possible. I stayed at a killer place on Maui (Napili Bay) for $107/night last year. I've stayed there few years before for about $130. Right on the water, freshly remodeled, all new furniture, kitchen stainless steel appliances and a 50" plasma on the wall.