"Saving puppies from pet shops," it sounds like a great idea!
The sad reality is that for every puppy that is saved there is another waiting to take it's place. As long as people are buying from pet stores puppies will be bred in disgusting and uncontrolled environments to satisfy the "demand".
As far as the person buying is concerned they have done a good deed, saved a pup. In reality they have proved yet again that there is a market for pups.
The only way to stop the puppy mills is to stop buying from pet stores and individuals that refuse to show you the mother with the pups and give exact details of the sire.
This is hard, it means leaving unhappy, cute, distressed and more often than not underfed and genetically inferior puppies in a bad situation at the pet store. It will, however, leave no openings for new puppies to be brought into the pet store and no market for the puppy farms. Tough love.
If you want to stop the trade stop the "rescue" that perpetuates it.