Petstores sell large numbers of small animals to all kinds of people who have no idea how to care for the animals. A large percentage of the animals end up in shelters--if there is room for them.
If you look on your local Craigslist site, a guinea pig will soon turn up, and then another, and another--in my city, there were several every week. Humane Societies, shelters, SPCAs, rescues-- any place there are pet stores selling guinea pigs, you can be sure that there are many sweet loving guinea pigs that need a home.
Please give one of these pigs a home!