I just happen to have bought some sand recently, and it isn't that cheap. Especially not the type of sand that you'd feel comfortable mixing into food.

Where I am, a ton of sand aggregate using in construction is ~$100 per ton. The better sand used in gardens, the brown sand (it's used to repel water so you don't over-water crops) is more than than.

Considering the wheat/ton spot price is $160 per ton at the moment, I don't think the actual prices would be too different.

[0] http://www.indexmundi.com/commodities/?commodity=wheat&month...

Perhaps it's 1% by volume instead of by weight.