Minis - you can print them on paper, you can use dice, you can 3D print them, you can use minis from other games, you can use Pathfinder minis.
Maps - you can print them for free (minus ink & paper costs), you can draw your own, you can use maps from other games. Even if you're playing a published adventure, you can still find maps for free online.
Books - you can pick them up second-hand, you can pirate them, you can borrow them. I also never fully understood the stigma against home-brewed campaigns - I strongly prefer both playing & running homebrew.
Maps - you can print them for free (minus ink & paper costs), you can draw your own, you can use maps from other games. Even if you're playing a published adventure, you can still find maps for free online.
Books - you can pick them up second-hand, you can pirate them, you can borrow them. I also never fully understood the stigma against home-brewed campaigns - I strongly prefer both playing & running homebrew.