vet bills, housebreaking, basic training, walks, CHEWING, food
And most importantly, health problems. Is your family willing to pay thousands of dollars to save Puppy from a horrible disease or health condition? Such as cancer, hip problems, etc? What if puppy turns out to be deaf, or blind. Or has Separation Anxiety. What if puppy grows older to hate children and cats, then bites them? Kids are to NEVER be left alone with a dog, even if it IS a puppy. Kids need to be 'trained' on how to correctly hold and punish puppy.
Puppies need to be taken out to go potty every 3 hours to help housebreaking. To even further assist housebreaking and separation anxiety, Crate train. Depending on puppies fill-grown size, crates can cost $50+.
You will also need to properly socialize puppy to people and other dogs by bringing your puppy to obedience classes, taking him/her to the petstore with you.
You will need a leash, several brushes(depending on breed), a collar, license, rabies shots, ID tag, METAL dishes(in case puppy is allergic to plastic, plastic holds more baceteria and stuff), puppy food, nail trimmers, PLENTY of chew toys, treats for training, and maybe more.
You need to set rules before puppy comes on, like whether or not its allowed on the couches, bed, etc. You should also contact your landlord/lady to see how many pets you are allowed to have. Then there is walking. Without a yard, a dog needs MINIMUM a 1 hour walk a day(again, depending on breeds). A hyper-active breed needs long walks, at least twice a day. Such as my puppy.
Of course, then there is spaying/neutering.
Anyone want to add on to this?