I have that thing from Walmart. It is useless to me. I hate it.
Now I use Kam Snaps. I was using snaps from snap source and hated the setter and the hammering.
Kam Snaps are so great and SO easy. Many colors and the best as far as I am concerned!
Shipping is really fast!
Here is the setter and check out the snaps. http://www.kamsnaps.com/Pliers-for-Plastic-Snaps-c5/