This combo kit provides all the primary structural and hardware components to build the robot. You do need to purchase the motors and drivers factory direct from Stepperonline. To keep the AR4 project as low cost as possible I dont mark these up, add any taxes, tariffs or additional shipping fees - purchasing the motors direct keeps the robot cost as low as possible. You also need to 3D print a number of the covers and spacers - this also keeps the project cost as low as possible not having to pay for injected molded components.