Having been to AKR many times, having been with the dolphins many times, having spoken with AKR divers about this issue many times, there is a clear answer - SNORKEL! Forget the money issue, it's about contact time and quality of that contact. When you dive with the dolphins, you wait while each person gets his/her few minutes with the dolphins. And that's all there is.
With the snorkel, you get to do a waist-deep encounter for about 20 minutes - typically 2 people with each dolphin. You get to touch, pet, look at, talk to, pose with the dolphin all you want. You then get to do an exercise with it (imagine lying flat on the surface of the water and having the dolphin come up behind you and push you around by your feet!). And then you get like 20 or 30 minutes snorkeling in a large, contained pen and can have as much interaction with the dolphin as you want provided you can be more entertaining than the others around you! Because the dolphins want fun interaction, things you do to engage them promote even more interaction. So it's not just swimming and watching them swim.
Yes, it sounds like diving with them should be more fun (i.e., more bottom time, no need to surface for air), but every person who dives with the dolphins comes back with a modestly positive reaction, every person who snorkels with the dolphins comes back with an ear-to-ear grin that says he/she had a great time, and everybody who dives and then snorkels with the dolphins says "why did I bother with the dive!"
Enjoy your trip!
Allen