So, you want a puppy! That's a wonderful idea, and a new puppy (or fully grown adult dog) can be a perfect addition to a new household.
Keep in mind though, that dogs are a handful, and they require a lot of attention. These needs don't go away when they grow up, or if they're already grown up when you get them, like what happens with kids. I'm not saying kids don't still need attention when they're grown, I'm just pointing out that the puppy won't start paying its own medical bills when it grows up, which is what most kids have to do, especially once they're out of their parent's house. On the other hand, a puppy won't move away, like most kids do, so there's an upside.
To the end that many people don't consider just how much work a puppy is, some of those responsibilities are listed here, at the risk of you deciding you don't want a puppy after all.
Deciding on a breed is something that many people don't take into account when they are on a search for a dog. In fact, a lot of people decide they want a dog, and then look at how each breed looks physically to decide which breed they want. Looks is an okay thing to look at, but it should be secondary to breed temperament and activity level decisions. A high-activity dog in an apartment complex isn't necessarily a good idea.
Puppies (or older dogs) have is the adoption fee, or the cost from the breeder of a pure-bred litter. That, to most people, is a no-brainer. There is also a cost if you find a puppy on the street, though. The very first of those costs is immediately taking the found dog to a vet to check them over, and make sure they don't have a microchip. Microchips are very common now, so a dog with no collar can still have a registered owner that can be found.
Once you buy or adopt them, you have to buy all of the miscellaneous supplies that goes with a dog - leash, collar, food bowl, water bowl, treats, food, toys, crate (if preferred), shampoo for baths, dog waste bags for walks, portable water bowls for long walks or trips around the city, and any other miscellaneous stuff that the puppy needs.
The next point is setting your puppy up for medical care. Many veterinary practices offer monthly plans that include vaccinations, rabies, and general checkups. Monthly plans often also have discounts on surgeries (such as spaying or neutering), medical tests, and prescriptions. Other offices do it on a visit-by-visit basis. You need all of those things mentioned above, whether you're on a monthly plan or a visit-by-visit plan.
Training is also an important part of getting a new puppy. If the puppy is little and really cute when it does something dangerous (such as biting) and you let them get away with it, it won't be little and cute when it grows up to be a 60lb monster that bites people. This doesn't always happen if you don't train your dog, but it could. Training is essential.
Training is usually thought of as being things like "sit", "stay", "down", "come", etc, so house training will be put down here in this section. House training is important, and can be a big responsibility if you happen to find a puppy who's resistant to the whole idea.
Puppies cannot hold it for more than a few hours, especially when they're really young. They also need a lot of stimulation, especially if they're the only dog in the house. This means that you have to find the time to be home with them (and play with them when you are home) a frequent intervals. It is very important for their development to have a lot of human contact, a lot of walks, and (after they are vaccinated) to be around other people, kids, dogs, and small mammals.
Dogs are amazing animals, and they are a wonderful addition to many houses and families. However, many people should (and don't) consider their needs when a dog is brought into a new home, whether puppy or adult. Take the information above as a suggestion when considering bringing a new dog into the house. If all of the above are done well, you will have a great new member of your family. Just keep in mind that it's a lot of work.