The average cost of owning a dog can vary greatly depending on a number of factors. According to the American Society for the Prevention of Cruelty to Animals (ASPCA), the first year of owning a medium-sized dog can cost anywhere from $1,314 to $1,843, while the first year of owning a large-sized dog can cost anywhere from $1,582 to $2,202. These costs include initial exxpenses such as adoption fees, vaccinations, spaying or neutering, and training classes, as well as ongoing expenses such as food, veterinary care, and grooming.