I just started newsprint after trying 2 kinds of wood chips and eco earth. The particle substrates took too long to thoroughly remove from the tank floor and eco earth got my snake very messy (though a tub would be easier, simply pouring it into a trash bag). It also left bits all on my carpet every time I took him out. After some humidity tweaking and lots of insisting from my very anti-particulate-substrate vet, I got a box of white newsprint from a storage warehouse.

For $13 I got a box of 3x3 sheets. There is enough in the box to last me a year even if I changed it weekly. The hardest part is just folding it to size, though my snake hasn't figured out how to get under it yet.