We have rock and sand.
I still have a full bag of tropic Eden reef flakes left over. Premium Aquatics recommended 4 bag, 120lbs. I bought 3 and only used 2, 60lbs total. That gave me about 2.5"-3" all around with a few deeper area in the back of tank. That should be plenty for any fish I add, for the most part. By the way this sand is awesome. Highly recommended. Still waiting on my sump. For the time being I'm gonna start off with a 15 gal
tank I have laying around, then when the sump comes in I'll just switch it.