Buying a guinea pig????????????

My aunt is wanting to get a guinea pig for her granddaughter for her birthday. i had them when i was little and loved them, so i recommended she get one for her. the problem is, when i was little, we bought them from the petstore. we didn't know better, and one even died when she was just a baby. her back legs were paralyzed for some reason and she got very sick. it was terrible. so i don't want her to go to petco (or any other petstore) to get her a guinea pig. my question is, where else can you get guinea pigs? do people breed them at their homes? would the local paper be a good place to find them? thanks for your answers.