You want the Midwest interactive Guinean pig habitat $49.99 on Amazon. Use fleece blankets on top of moving blankets instead of sawdust. Go to a moving company and buy one of those blankets they wrap pianos in. Super absorbent. Cut one layer to size and then cut fleece to size for on top. If you are really fancy, you can sew them together. You can use a little broom and dust pan to sweep up the poos and then switch out the blankets once a week.
Guinean pigs are social so you'll need a pair.