Its pretty hard to find holey rock at a local supplier anywhere but in the area of texas you can find it. I was in Texas and I could find it available anywhere, but I've heard around El Paso is a good place.
That said, I found a nice rock for $10 at a garage sale here in Cali. Lucky find, these people collected rocks across the country in an RV. If you work hard and don't want to pay the price for online rock purchases, check craigslist and post wanted ads for decorative rock and see what kind of responses you get. Sometimes enough of that gets you nice rock.
I tend to side with people using rock that is locally available, makes for diverse tanks depending on where you live.
People in the midwest can get cheap limestone rip-rap that looks great, where I am my options are sandstone and granite, not my favorite choices, but sandstone does have some advantages. In texas, Holey Rock and other limestones are also common.
Wish I could help you more...just keep checking more places and eventually you will get lucky.
i can get holey rock. i have a place in west texas that i go to about once a month. i can get as much as people are interested in. shipping would be expensive but the price would be 1$ lb. pm if you are interested because i will not be checking on this thread. thanks shawn.