Where can you purchase animal grave markers?

I found a website called peternity.com They had a guinea pig grave marker in a nice slate, They seemed a bit expenisve though with $75 seeming to be the lowest price. They do add custom epitaphs though and can also upload your own drawing of your pet or a photo if you'd like. I've never used them so I have no exprience with the outcome of their work. I have used a site called Rock It Creations in the past but they did not have a guinea pig stone. I loved their work though and they too can ingrave custom artwork. They are also a bit expensive but I loved finished product.

I looked at the 4paws forever website and it looks pretty good. I would go with that. Here is their "symbols" list. There is a guinea pig symbol near the bottom. www.4pawsforever.org

There is a company called 4Paws Forever that does pet markers that are pet specific and I know they do guinea pigs. They have an online website www.4pawsforever.org

I am not sure exactly what your friend is looking for, but I got Brandi's memorial stone from Old World Stones www. oldworldstones.com Brandi's was a custom stone made with her picture and they can do almost anything you want.