I use peat moss-organic soil mix, about 50-50. It hold moisture well and it's dirt cheap--Pun intended! It cost me $15/year to fill 2, 4'x4' enclosures with 5" of mix. It's due for a change now, after a year.
May, Aussies, & THBs
IG: @AUSSOMEAUSSIES
May, Aussies, & THBs
IG: @AUSSOMEAUSSIES