This biting problem is very normal considering the age of your dog. The puppy is going through Teething which will last for another 4 months or so. After this period the period of Adolescence will start during which this chewing habbit will go almost completely. My puppy is also of the same age and he loves to chew on my hand and when asked to stop he growls and barks. This behaviour is normal among puppies. I have however reduced this habbit considerably by 1) Making a provision of raw hide bones and toys, these keep the puppy busy and he woldn't try to chew on ur hand. 2) When the puppy does try to play with your hand, assertively say "NO" and the moment he stops reward him by saying good boy and offer him a treat. If he continues take your hand off him and offer him nothing. This will convey him a message that playing with your hand won't land him anywhere and this won't be rewarding either. Trying to intimidate the puppy by showing a newspaper won't solve this problem in the long run. Offer him his favourite chews spend a little money buying them from a good petshop. Why do you want to spend fortune on training when this trivial issue can be taken by you on your own. And keeping the dog onleash is sheer stupidity and I don't recommend that. I keep the dog on leash only when I think I can't keep the puppy under supervision for a while like half an hour or so, or when floors are being cleaned, not otherwise. Your puppy won't learn anthing by being tied on a leash throughout the day and you can't take the best out of him. Read some book about dog training especially if it covers the breed of your on puppy, read some articles about 'Positive Reinforcement'. That certaining gonna enlighten you.