This document provides a yearly cost breakdown for owning a guinea pig as a pet. The estimated total cost is $295 per year, including $108 for food, $60 for a cage, $6 for an igloo, $72 for bedding, $7 for toys, $16 for a pen, and $6 for grooming supplies. It notes that the listed cage is a starter cage so additional bedding would not need to be purchased.