| Tony,
I think you can skimp a bit on the live rock at the start. I would get enough live sand to get the bed to the depth you want and like. For me that would probably be 40 lbs in your tank. If you pick up 5 to 10 pounds of live rock on top of that you can mix in regular rock which will cure overtime. There are articles about making your own concrete rock and curing it on the Internet. They claim you can drive the price down to $.25 pound. I have not went that far but I think curing rock is reasonable (it just takes a little longer)
I am not sure how much you know about all of this but I would suggest that you read and understand the sticky post on cycling |