A pet owner should be willing to spend good money every year. The bare basics for any pet will include a place for it to live, food, a water bowl, a food bowl, and toys. Toys often wear out within a couple of years, so every pet owner ought to be ready to replace them as they wear out. Other animals have special needs.
A dog needs a collar, a leash, and probably both a dog house and a pet bed. A cat will need scratching toys, a cat bed, and possibly a collar. A rabbit will need a wide cage and a lot of time invested into playing with it. Not to mention the cost of the rabbit pellets and the cage.