JRScuba is correct. There are cheaper 'BOATS'. But the cost of diving is going to be about $75 even with Jerry and Parrotisland. He charges $10 per tank as most other ops do. I think he is at $45 or $50 for the trip. So the trip and two tanks is at about $70. His boats, the Fathoms'o'Fun and Fish Food are very good and sit at the corner of the inlet so there is no channel trip whatsoever.
Another good guy in the area is Bryan at Scubatyme. He works his butt off for $60 per person and even changes your tanks as he is the Captain/DM/Mate all on his own. However, you never feel neglected even though he is doing all the duties. If there isn't a preset trip, he will be glad to do the dives you wish to do.
Good luck in your search of cheaper ops, but it will take more than luck to find someone willing to take you out for less than $40.
Another good guy in the area is Bryan at Scubatyme. He works his butt off for $60 per person and even changes your tanks as he is the Captain/DM/Mate all on his own. However, you never feel neglected even though he is doing all the duties. If there isn't a preset trip, he will be glad to do the dives you wish to do.
Good luck in your search of cheaper ops, but it will take more than luck to find someone willing to take you out for less than $40.