10days in fiji

so ive got 10days in fiji for some reason on my flight from la-sydney end of march/beginning of april. Was thinking about going to the beachouse as i wasnt able to stay there last time and really want to for no real good reason, but i really also want to go to the yasawas, maybe octopus or manta ray island? Any other recommendations? Im a single guy, late 20's, been to fiji before but broke my foot first night there so it kinda ruined it that time, so im pretty much up for anything.

also, what kind of cost are we thinking for 10days in fiji?

thanks all!