For substrate, Aspen is what's preferred by most people around here. I recently switched to it myself. It allows the snake to burrow, and is easy to clean. When your snake "takes a bathroom break", you simply remove the dirty area. This is what we call "spot cleaning".
A bag of Aspen costs about $8 but lasts around a month, as long as you keep everything clean. Do NOT use cedar or pine, as those are toxic.
As far as Hides go, you can use just about anything that the snake can fit comfortably in and be able to hide. Cut up cereal boxes, etc. Just don't use anything that hasd chemicals in it. And not something too big, as snakes generally want to be snug.