I just looked through all the brochures and papers I had in my file from visiting Atlantis a few years ago, and couldn't find anything that would help you with prices for any activities or extras
I would make a call to Atlantis and ask for the Concierge Desk and get a definitive answer as to what you will be charged extra for, and how much.
I think you can probably go there and partake in all the included activities (beach, pools, etc) and be perfectly satisfied, but I think it's worth a call to see if you will be charged extra for The Dig, the slides, etc.
This place is known to break the bank.
Maybe one way to save a few bucks....TravelZoo just came out with a deal for rooms at Atlantis for the month of May for $199..... an excellent deal.
www.travelzoo.com
Have fun.