Hey, you might want to check out any mineral companies in your area. I just bought some nice sand from a local mineral company here in Washington. I couldn't find pool filter sand anywhere here. Home Depot, Lowes, Ace Hardware, McLendons checked them all, none of them carried it. LFS wanted 44$ for a 100lb bag.
Went to mineral company, they broke out this container that looked like a plastic tackle box, it had about 30 different pool filter sands with different colors and different grain sizes. I ended up getting 200lbs of the sand i wanted for 44$. They also had all kinds of different rocks, sizes...ect. So, if you have one in your area, that would be the first place I'd check.... Will save you a ton of cash flo too =)