Fiji is a remote Pacific island; $300 pp RT to any major continent is a bargain! Have you even looked at a map yet
If you haven't booked your tickets yet at all, I agree looking into a ticket that includes a stop in Fiji and a destination of NZ or Australia. That might help bring the price down and you wouldn't have the hassle of separate connecting tickets on your return.
So search for US-FIJI (stopover), FIJI-AKL(destination), AKL-US. I'm just assuming you are from the US since you didn't specify...