Cavy Cages has directions to make your own inexpensive C&C cage for guinea pigs. Martin's Cages makes great rat cages. They also have cages for just about any other species you can think of. KW Cages a good source for rabbit cages.
Supplies: CozyCavy has been spoiling guinea pigs around the world since 2006. In addition to being able to purchase items for your own pigs, CozyCavy has a program where you can donate CozyCups directly to Wee Companions for 50% off. Cats & Rabbits & More a source for fun things for herbivores. Kleenmama's Hayloft a good source of quality bluegrass and Timothy hays. GuineaDad offers high-quality products for small animals.
Kavee offers cages and other supplies for guinea pigs.