That doesn't all have to be live sand. You can use Southdown playsand for 180lbs and then toss in a 20lb bag to seed it. Shouldn't cost more than $50 for all of it. ~$4/bag of Southdown 50lb bags and ~$35 for 20lb LS.
that would be my pref, however, i can't seem to find the southdown playsand in hawaii. i may just take a boat out and pull some sand from the ocean floor. we can legally take 5 gals/day. that should allow me to get 50lbs/day.