Don't be afraid to ask LOTS of questions...where is it used to sleeping, eating, when does it eat, does it come with a health guarantee and shot records, OR ANYTHING you can think of!
I am sure the owner won't mind you asking questions! If they do or the answers seem odd to you...don't be afraid to tell them you want to think about it! We are always glad to explain anything that may seem odd to you!
If its a great puppy, and the owner has great answers to all your questions...then don't be afraid to bring it right home! LOL