I am going to get an adult leopard geko. how much do i feed it and how often?

also do i have to constantly have a dish of mealworms out for him? because all that vitamin supplament and all of those mealworms will start to cost a bit much. i also can't keep them alive forever so i'd have to go to the store every day. Could i just use frozen thawed? the breeder says he tries raises all of his herps on frozen and thawed. i also need details on the vitamin and calcium suppliments.