I was buying mine from Walmart, I like how thick they are but they didn't have any this past weekend so I ended up with an economy pack from Petsmart, I dont like them at all, they're super thin so now i'm stuck with 150 of them.
This is the one I got from Petsmart
Simple Solution® Economy Puppy Training Pads - Training & Behavior - Dog - PetSmart
And this is the one I love from Walmart
Walmart.com: Blue Ribbon: New! Housetraining Pads, 50 ct: Dogs