I can't think of the brand right away, but those blue bags sold in spools to go into those little plastic leash things are biodegradeable. At least the ones I buy at Petsmart are. It says it right on the package. I don't use the leash thing, but just buy the spools and tear off each bag like at the grocery store when fruit shopping. I think there are 30 bags per spool, and a 9-pack of spools was like $10-$12.
I also just save up plastic shopping bags while I'm using the blue ones, and use those when the blue ones run out.
I also just save up plastic shopping bags while I'm using the blue ones, and use those when the blue ones run out.