Bro, thats not all you need to gain muscles. You need to have 5 to 9 meals a day. Eating eggs, bananas, milk and some meat wont cut it. You need to do more than that. I would say, the average price would be somewhere from 30,000 to 50,000 a month. I am going to post a bodybuilding diet for beginners and you can estimate how much it costs.