Pet stores are notorious for jacking up prices, getting bedding, and hay at feed stores can drastically cut your costs. Keep in mind that plain green pellets are just as healthy as the fancy pellets that have all kinds of color full goodies, some guinea pigs even prefer the cheaper, plainer pellets. Many pet stores try to convince to buy their deluxe, yet expensive, guinea pig cage. As long as you have 2 square feet of room for one guinea pig and an extra square foot for each additional guinea pig, you'll be fine. Instead of buying an expensive cage you can opt for some cheaper, yet just as robust options.
Many department stores sell large storage bins and small children's wading pools.
As long as the sides are 12 inches or higher these cheap alternatives make great cages. Interaction Guinea pigs are very social animals, but don't need much to keep them happy. They don't need to be walked and their cages are relatively small. If you spend most of your day at work or school, housing two guinea pigs together is your best option. Two guinea pigs will keep each other company and not become lonely during the day.