Well, Ace hardware here and our Menards has plenty! Ace has some in three different sizes I believe, and it's about $3.50 a bag.
In the pet dept. they sell some really large nice pieces, but buying this way obviously gets a little pricey. They don't have a whole lot, but it would get you started. Nonetheless, they have what you are looking for! Otherwise, I thought that Aquatic Imports in Appleton has some. I know a they are SW, but I know for a fact that they have holey rock for cheap and I swear I saw lava too.
In the pet dept. they sell some really large nice pieces, but buying this way obviously gets a little pricey. They don't have a whole lot, but it would get you started. Nonetheless, they have what you are looking for! Otherwise, I thought that Aquatic Imports in Appleton has some. I know a they are SW, but I know for a fact that they have holey rock for cheap and I swear I saw lava too.