I know you are not supposed to buy a puppy from a pet shop because they almost always come from puppy mills. But does anyone know if thee is any such thing as a guinea pig mill? Just curious.
If you want a guinea pig, go get one from the SPCA I volunteered for many many years at the local animal shelter with a rabbit rescue group, and we almost always had a few piggies too (usually young ones--they were gifts for the kid who got bored of them within 6 months)
If you are looking for one, i would wait a couple of weeks and check craigslist
because of the new movie about guinea pigs, many people went out and bought them sooo they will probably be looking for new homes soon