Depends on where you get the stuff. You'll probably be looking at somewhere in the area of 100-150lbs of sand. My lfs sells it for a dollar a pound, but it can be had for cheaper online. LR... most people recommend 1-2lbs per gallon for a good reef tank. LR at my lfs goes for about $7/lb, but again, you can get it cheaper online.
At LFS prices...
125lbs LS @ $1/lb = $125
1.5lbs/gallon = 75lbs of LR
75lbs LR @ $7/lb = $525
$525(LR) + $125(LS) = $650.