I think it depends on the specific pet. The most expensive pet we have is Izzy, our iguana. Izzy eats fresh vegetables and fruit. His lighting is ridiculously expensive, his UV light costs $100 and needs to be replaced annually. Izzy has a bedroom-sized room all to himself. In that room Justin built him an iguana jungle-gym, I have no idea how much we spent on building that, a few hundred dollars at least. Justin still has to get a bathtub and plumbing in his room, that will be cost between $100-$200. Izzy also has his own air-conditioner to regulate the temperature of his room, that cost $500. It also costs money to run the AC and his lighting.