My local PetCo's sell their 4.5cuft bags of pine for 10.99, but I've found a local pet feed and supply shop with 5cuft bags for 7.99. Shop around, you'll find something somewhere. yellowpages.com is your friend...

As for the shredded paper, don't bother. I used to use it way back when and my rat and mice bins smelled bad at day's end.