honestly on threads like this one that the subject has been beaten into the dirt your search engine on bp.net will be your best friend.
You can find plently of useful information on past threads by searching for the key words.hope that helps you.
But to answer your question i use newspaper, its cheap, and the snakes can hide under it. the cons on newspaper is it can get bunched up and not cover the bottom of the tub and its not very absorbant for urine.