Another alternative is to do the boat diving package, but a group of people will get together and rent a truck for the week so that they can go to other shore dive sites during the afternoon/evening, and visit more distant restaurants on the evenings we're on our own for dinner, and lastly so they can explore the island on the off-gassing day. Whether you rent for a day or for the week, I'm sure you'll be able to find others to help share the cost of the vehicle.
The best vehicle to rent is the dual-cab truck that seats 4, and it has tank racks build into the pickup bed. You can get tanks from the resort.
Word of warning: if you shore dive with a truck, leave NOTHING in the vehicle and keep the windows rolled down. The only real crime in Bonaire is the petty theft out of unattended diver vehicles. Bottles of water are probably safe, but nothing else is.
Have been looking at some well reviewed shore diving sites. Anyone interested in getting together on a truck rental?