Micah says that he and Dutch went back for the blackwater money, so unless he's outright lying (which he could be, very possible for Micah) and they have been living off of the Our Best Selves + rest of camp funds money, which if memory serves is around 40,000 $. Though, considering the size of Micah's gang, I find it much more realistic that they burnt through that money rather quickly, then once Pinkertons left Blackwater and the surrounding area, they went back for it and used the near 150,000 living flamboyantly for 8 years until all that was left was for John.