Sand, " easy. " Ha.
Theres a lot of discussion and debate on that one subject alone...
What type such as aragonite verses crushed coral or gravel and how deep is best for denitrfication or to keep alive with critters or to keep it clean and what size as in small grains or larger and some people dont even use a substrate in their tanks ( bare bottom ) and whats best with/for certain species or what species is best with certain substrates, ect., ect., so on and so on.
Many laws now about collecting youself and IMO thats a good thing.
If you decide you want a tank with fish that can not be in with corals or crustations, aka, fish only or aggressive tank, then intensity and wattages of lighting is not as important. If you want a reef, then it is very important.
I have 200 lbs of Figi LR in my tank and about 30 more in the refugium filter/sump. I have not bought LR in a long time so Im out of the loop on the best places, sorry. May want to just try to find some nice ones locally, will cost more but at least you see what you getting. Pre cured can help speed up cycle some as well.
I understand the excitement of wanting to quickly have your tank nice and stocked, but once again I must suggest to have patience and take your time and continue to learn as much as possible.
Thanks for the compliments. Didnt want to discourage but hoped to incourage you to want to do things right. hehe