What dirt should i use?

Ya i know im a noobie and this is the noobie section so dont hate on me lol. Should i actually buy dirt from the store or just dig some up out of my friends back yard?

If i need to buy the dirt what dirt should i buy?

Don't use the dirt from your back yard that's just inviting bugs into your grow room. I use FoxFarm Ocean Forest but any potting soil that does not have any nutes in it will be fine.

Worm castings