woah woah. You need to slow down. Getting a dog is never something that should be done on a whim - you're talking about taking on 12 to 16 years of responsibility for a creature that will depend on you for everything.
What is your living situation? Apartments aren't good for larger dogs, and even smaller dogs still need somewhere to run.
What is your work situation? Are you planning on getting a puppy and then leaving it at home for 10 hours at a time while you work? Is that fair to the puppy?
I'm not trying to rag on you, but your post shows that you need to learn a LOT more about dogs before getting one.
To answer your questions more specifically, though, you should expect to pay between $300 and $1000 for a good purebred animal from a reputable breeder.
You should ONLY get animals from a reputable breeder or from the animal shelter. NEVER buy a puppy from a pet store - most of their animals come from puppy mills, which are nothing but cruel animal abusers -
http://www.hsus.org/pets/issues_affe...lls/index.html
You should never "go with your instincts" - you should research breeds to find the breed characteristics that are most compatible with you. Then you need to research the breeders you are considering to make sure they are working to eliminate genetic problems, otherwise you could wind up with a very sick pup on your hands.
Bottom line, dogs are perpetual 2 year olds, and they require every bit as much care and attention as a human 2 year old. If you don't know what you're in for, you'll end up with a bad situation for both you and the puppy.