Head to Amazon for a great deal on Merial Frontline Plus Flea and Tick Control for Dogs and Puppies, 6 Month supply. Get it for around $60 regardless of the size of your dog. Other online pet supply stores have it for as low as $75. Just choose your dogs weight to see the price. Rates are also great on 3 month supply; but you get the better deal on the larger quantity!
Head to Amazon for a look!