In the main story, Undercurrent subscriber Jim
Willoughby compares the costs of booking group trips
to various locations. He doesn't do it for a living, he just
gets a group of his diver friends together and handles
the bookings, negotiating discounts with dive resorts
and liveaboards.
"Joe Diver can negotiate," he says. "It depends
  on the size of your group, and on the flexibility of the
  resort. But if I am bringing 10 divers, I often either pay
  for just eight of them, or negotiate a 20 percent discount.
  What I save, I spread among the group."
Subscriber Guy Charlebois (Laval, Quebec) is
  another non-travel-professional who regularly negotiates
  dive group trip discounts. While his wife is a travel
  agent and handles the flights and hotels, Charlebois
  researches dive operators and asks what they can
  do for him. When his group of 12 divers wanted to
  go to Cozumel last December, he e-mailed four dive
  operators and asked what they could offer. He chose
  Dressel Divers as it offered a 20 percent discount off
  its "Gorilla" package (eight reef dives, one night dive
  and two cenote dives) if he paid in advance. "For other
  trips, I usually get 10 to 20 percent off the regular price
  if I have a group of 10 or more."
Ann Louise Tuke of the dive travel agency
  Caradonna Adventures says some resorts offer free
  spots for groups with as a few as five or six paying divers.
  While some resorts do require a group to be formally
  organized through a travel agent or dive shop, there
  are plenty, especially smaller ones, that offer reduced rates to personally organized groups. Tuke says it's
  easier to get discounts when it's not high season. "And
  it doesn't hurt to call a travel agency and ask for help in
  getting discounts. Caradonna tells divers where to go for
  discounts, even if it won't get a booking commission. "If
  someone calls us asking, "'How many people do I need
  to get a free space,' we have that information and pass it
  on to groups, whether it's a formal group or a bunch of
  friends," Tuke says.
Willoughby says the Philippines seems to be most
  amenable to giving a package deal. Indonesia hasn't
  been as flexible. The Caribbean is more flexible, but he
  says their standard rates can be much more expensive.
  "Like at Anthony's Key in Roatan, the rate is considerably
  more than a comparable package almost anywhere
  else, so negotiating doesn't bring it down to an
  attractive price."
To get the best deal, Willoughby recommends
  researching and booking early. "I start a year out. I'll
  research a liveaboard or resort's rack rates online, and
  then I reach out with questions like 'I want to bring
  some friends, do you offer a group rate? What kind of
  arrangements should we make?' They get back with an
  offer and generally it's pretty good. If I counter-offer,
  sometimes they come back with a different program, or
  sometimes they say 'No thanks.'" Willoughby is proud
  of the "killer deal" he got when booking a Raja Ampat
  liveaboard for 2016. "They gave me this current year's
  rate, plus a discount to that, so a 12-day, all-inclusive
  trip that would cost $4,600 per person is only costing my
  group $3,100 each."