#2 PetZoom Pet Park ($39.99)
The PetZoom Pet Park Indoor Pet Potty is a three tier system measuring 30" x 20" inches. At $39.99 with Free One-Day Prime delivery this is a great option if you need something in a pinch. With roughly 1000 reviews on Amazon, this product has made many dogs and dog parents happy.
#3 PETMAKER ($28.01)
This is the best selling synthetic grass system on Amazon. While it is not as fancy as the Pet Loo system, the PETMAKER Puppy Potty Trainer is a very economical solution. The product comes in both Small and Medium sizes. Both sizes ship via Amazon Prime.