I recognize that image.
Head over to your local Japanese Garden Shops, particularly ones that specialize in Bonsai gardens. You can find Seiryu-seki and ohno rocks there for pretty cheap. Well, cheaper then what you would pay for them at the ADA places. I'm lucky to have a japanese shop that's right across the street from Aqua Forest Aquarium (the ADA store in San Francisco). Ended up saving up to $3 dollars per pound on the same rocks.
-John N.