I dove at the Living Seas in February and had a great time. Like the PP, I got a discount - but mine was using
AAA. I paid $119. The DVD was $35, and I did purchase that also. They let you view the DVD before you decide if you want to buy. I did bring my own mask. Everything else, down to the elastic band for my hair was Disney's. Everything was included in the fee, except the DVD. So the fee includes all your equipment, the dive itself, a backstage tour, a tshirt, the certificate, beverages and a pin. I think the entire experience took almost 3 hours.
The tank is about 25 ft deep, can accomodate all of spaceship earth with 10 feet left over, and I believe the dive was about 40 minutes. It does not include the area where the dolphins are, although you can see them through the bars. Definitely have friends and family watch - I was the only one in my session who had guests outside the tank with me, and it was SO much fun. They got to be on the video too. Disney takes you on a backstage tour, and then you go to the locker rooms and change. You parade through the pavillion in your wetsuit in order to go up to the accesspoint for the tank (which is HUGE). Everything is all set up for you, so you just slip into your gear and then descend with the instructor. They took you on a tour around the tank, to the dive bell, where you pose for the video, and then after you are pretty much free to explore. After, you go back through the pavillion, dripping wet, to the locker area where you shower and then back to meet your dive group to watch the DVD and have a beverage. I had a great time and would highly recommend it. Great animal life, and very unique experience with the guests.
I went on my own, and had a good time. Everyone else there was diving with someone else. My 2 criticisms are (1) Disney really didn't faciliate hooking me up with a buddy, and we got into the water so quickly that I didn't have time to do it either. (2) The locks in the locker rooms did not function well, and the Disney folks lost the key to the locker room keys, forcing us to wait in our cold wetsuits for about 10 minutes. The key situation can definitely be improved.
One other note, you do not need park admission to get into the program, and they will let you stay at Epcot free after. They have multiple slots a day, including some that are purchased by local dive shops and not available to the public, so it doesn't matter what time slot you pick. I picked a later slot in the hopes I would get a longer dive, but there was a dive shop group I was unaware of after me.