I don't cruise, we were there for a week and dove with them one morning.
Taxi. That
should be less than $20 r/t although the rate goes up when your ship docks...
(negotiate in advance) I rode from the West End to Coxen Hole, a much farther trip for $15.
On our boat there were 6 of us. My group only. They only take 8. Barefoot Cay is a small resort, we only saw two other people there all morning except for their staff. So it might be just you two - IDK. Not everyone staying at Barefoot is a diver either - it's also a small marina and has nice villas on the beach. We were there the 1st week of May - low season.
Comfortable Boats - Your Limousine Awaits!
* All 4 boats have sun covers, fresh fruit, water, camera rinse tanks, and dry towels
* Equipped with emergency first aid, oxygen, and floater lines
* Groups are small: maximum 8 divers plus boat captain and instructor
It's your call, you can either do two average dives with a 1/2 hr. shuttle ride each way or spend a little more $$ to do a dive that's among the best on Roatan - I know what I'd do. Were Barefoot to take you to Calvin's Crack or Insidious Reef <- not likely - also, you'd likely have done two of the best dives on Roatan. Prince Albert (that we did) is one of the more known dives also.
I doubt that all of the other divers on the AKR boat off your ship are at your experience level either - the dives will reflect that. There can be 20 divers on any of AKR's eleven boats - the four bigger Pro48's they'll mention 30.
The only way you'd get a private boat is to do the Dolphin Dive since the site is 60' and a flat sand bottom, they don't take regular divers there. Also you go to the cay first to meet "your" dolphins. Someone here mentioned that the Dolphin Dive is $200 through their cruise excursion. Which seems like a cruiseline ripoff since we paid $122.
If you're looking for the cheapest thing, neither of these are it. Take a cab to the West End and dive with someone there. But you won't save much, have a longer ride, and probably can't get there in time for the deeper morning dives - it will depend on when you arrive, get through Mahogany Bay customs/immigration and get a cab. I have no idea how long that takes but it's generally almost an hour at the airport - we've done it twice recently - two planeloads - not 3000 cruisers.
We dove with Coconut Tree Divers in the West End all week, they're $35/dive ($30 if you're bringing your gear). We had a couple of different cruise divers on our 1PM boat twice during the week, but they did one (shallower) dive then had to leave to make their sailing.