Larcat, are you looking for rocks or gravel?
If rocks, what kind?
Rocks. I'm pulling a bunch of plants from my 7.5 gallon cube soon to put in my 55, and am planning on converting the 7.5 to an iwagumi for a variety of reasons. Looking for stones that have that "craggy weathered" appearance, but have no interest in paying out the nose for cleverly branded rocks from overseas.
this might be too spency for you...but Old Town Aquarium has some decent selection rocks, usually $3/lb i think...can call to check. beats paying that amount here on SNS and having to pay shipping on top of that.
I would go too a rock yard. pretty sure the rock I got from the landscaping yard is what you are looking for. I got bluestone (go by the bolder section and pick up the smaller sized rocks), looks nearly identical too ADA's "Yamayama stone" http://www.adgshop.com/product_p/yamaya.htm
I forget the price they quoted me but it was like 10 cents a pound, and they gave me it for free because the guy working said "these are too small for us too use on jobs anyways" or something along those terms.