where can I find a hard plastic baby pool?

You can buy a hard plastic baby pool at Walmart or online at http://www.Walmart.com

It took some online searching, but I found the hard molded plastic kid pools at:  http://doitbest.com/Wading+pools-Gen+Foam++Pools-model-DB-GV242D-doitbest-sku-833134.dib#online

There you will find a 60-in, a 45-in, and a 60-in with built-in slide.  For free shipping, you just put in your zip code to find a ship to store location nearest your home.  They also mention that if the store carries these pools in the store, they are not required to sell them at the online price.  After you find your closest Do It Best store, I would call and ask if they have any in-store and the price.  Then you will know whether it is cheaper to buy in-store or to order online and do a ship to store.  They say a ship to store will take 7-10 days.

Some ACE Hardware stores carry a 45-inch hard molded plastic kid pool.  So you might call your local store and ask.  

I have personally seen these hard plastic pools outside of Walmart in the front with the seasonal items.They typically do not sell them online because of shipping issues. They also have them in seasonal at Toys R Us. If you have a small 5 and 10 nearby they usually always carry the pools as do local pharmacy chains. Sometimes they are called sand pools as well and are used as a sand box. Pet stores carry them as well as people use them for small pets to run around in or for dogs to swim in.They are the same pool as kids use though.

Having a hard plastic baby pool ensures that it is sturdy and durable enough for your baby to have long lasting fun during the hot summer days. Your baby can keep cool in the new hard plastic pool that I found for you. Toddler Kiddie Snapset Plastic Wading Pool can old up to 121 gallons of water. This will make it much more fun. You might want to consider a plastic pool also because storage is so much easier and you can take it along with you if you are going on a play date

You do know, that hard plastic pools for infants are going away. In a few years there will be only inflatable baby pools.
But for now I recommend this Butterfly pool and Sandbox....
Unfold the wings of the Butterfly Beach Sandbox And Wading Pool to splash in the pool or play in the sand. Colorful shade umbrella keeps little ones protected from the bright sun. Emptied pool side becomes a secure lid to keep sand protected from the elements. Stores neatly and compactly.

Features

Unfold wings to splash in the pool or play in the sand. Colorful shade umbrella keeps little ones protected from the brigh sun. Emptied pool side becomes a secure lid to keep sand protected from the elements. Stores neatly and compactly.

I remember playing in one of these! Great summer fun.
Your kids will love to play in this Exotic Reef Snap set Pool decorated with bright tropical fish. Dogs also love to cool off in this pool! Snap set Pools are a snap to set up! Simply unroll and fill with water.

Hope this helps!