This is a children’s song used as a kind of gleeful filibuster to wear parents down in to buying a dog or other pet. There are not set verses and it's easy and fun to make up your own.( though now pottedstu tells me a version of the song was written by Bob Merrill 1924-1928)

How much is that doggy in the window? (woof, woof)
The one with the wiggly tail.
How much is that doggy in the window? (woof, woof)
I do hope that doggy's for sale!

How much is that Kitty in the window? (meow)
The one that purrs so so sweet
How much is that Kitty in the window? (meow)
I do hope that Kitty's for sale!

How much is that Bunny in the window? (hop)
The one that goes hip-ity-hop
How much is that Bunny in the window? (hop)
I do hope that Bunny is for sale!

I must take a trip to California (or insert place of your choice)
And leave my poor sweetheart alone
If he has no dog he'll be lonesome
And the doggy won't have a good home