Man's best friend can cost you a pretty penny -- from exams and vaccinations to prescriptions and medical insurance. By Sean O'Neill April 30, 2006 1. Buy the puppy in the window, not Windows. Americans buy about 150,000 puppies a year, sight unseen, on the Internet, says the American Pet Products Manufacturers Association. That leaves you little recourse if the deal goes sour. Only ten states regulate breeders selling puppies online, and no federal agency does.2. He'll chew your credit card to bits. A purebred will cost you about $500 for a Labrador retriever, the most popular breed, to as much as $1,500 for a Chihuahua, this year's fashion-accessory dog. Veterinary exams and vaccinations recently averaged $260 a year for canines, and preventive medicines for fleas, ticks and heartworm tack on another $200. Food and extras, such as leashes and pooch toys, push the bill still higher. 3. Prized pooch -- or one sick puppy? Most breeds are at risk for inheriting diseases that can cost thousands in medical bills and shorten your pet's life. For example, Samoyeds are prone to diabetes, and Boston terriers are at risk for tumors. Skilled breeders routinely take precautions when mating dogs. Exhibit A: Good breeders of golden retrievers will give new owners proof that the Orthopedic Foundation for Animals has certified that their mating dogs are free of hip dysplasia, a hereditary disease that can make dogs lame. The best breeders will guarantee your puppy's health for a reasonable period, such as a few months. Look for referrals from your local breed rescue club or the American Kennel Club. 4. Your pet policy may be all marketing, no bite. Medical-insurance policies for pets are increasingly popular. But many fee-for-service policies cap the amount they will pay for specific injuries and illnesses in a given year. These caps are often so low, says Robert Hunter, insurance director at the Consumer Federation of America, that you'll still pay a large portion out of pocket. The alternative is a discount plan, such as Pet Assure (starting at $99 a year; www.petassure.com), which slices 25% off the cost of routine exams by participating vets. If you own two or more dogs that need more than routine care, the savings will offset the fee. Advertisement 5. Your dog's ulcer gives you heartburn. Filling prescriptions through a veterinary clinic can be pricey. The reason: Clinics often don't join with other clinics to buy in bulk at a discount. For example, many vets prescribe Rimadyl, an anti-inflammatory drug, to treat dogs suffering from arthritis. The drug costs as much as $70 a month at a clinic (for a 100-pound dog). But if you buy the same drug at 1-800-PetMeds, an online pet-supply store licensed to sell medicine in every state except Indiana, you'll pay $33 a month. Note that many drugs prescribed for humans are also used for animals. For example, Tagamet, which relieves heartburn in humans, is used to treat ulcers in some dogs. National chain pharmacies often charge as much as a third less for these drugs than some veterinary clinics. Another tip: Ask your vet if he or she can prescribe a generic drug.