Middleton dog doors are available in all sizes and shapes and are developed for several types of doors. A flyscreen dog door costs around $15 and up. It is considered to be the cheapest kind of dog door. A solid dog door on the other hand can cost between $30 and $75. A dog door that can be installed in a sliding glass door can cost you around $200. The microchip dog door that is specially made to only allow a pet with an RFID collar to enter the house can cost around $275 or more. The most expensive one is the customized glass dog door that is typically priced between $350 and $700.