depends on what kind of tank. 1-1.5 lbs of lr for a reef, but if you're not going reef, then how ever much you want. with sand, do you want a dsb? or just a few inches?
live sand, and enough to make the tank keep clean. i would like like 25-30lbs of rock i think that will be enough. can i use regular rocks from outside in my yard in my tank? like as a base for the lr? and just thrown in to look good.
You can use just regualr rocks for a base but you have to be sure of their composition as some rocks can leech chemicals into your water especially those from the "gardeor backyard".