Walmart offers the Bio Bubble Activity Pod in White for $14.50. (Amazon charges the same with free shipping for Prime members.) Choose in-store pickup to avoid the $5.99 shipping fee. That's the lowest price we could find by $4, although most retailers charge around $25 more. This modular playground is suitable for small animals like hamsters, gerbils, and mice and features a hammock, whisper wheel, food cup, and water bottle.