Walt Disney World??? What woul dbe the average cost to go?

Ok so my parents were talking about going to disney world in florida in the summer. we would take a train there so we dont have to worry about the cost for plane tickets. All we want is like this; A really nice place to stay (particulalry for kids obviuosly), Nice places to eat, fun activities and stuff, and I think there are... pools at the resorts??? idk but im a kid was just wondering... lol but please my parents also want to know an average cost so i took the advantage and asked you myself! thanks! :)