Great Barrier Reef Cruise
The Compass reef cruise was advertised as $60 but was actually $80 with taxes, fuel levy, etc. That's still the cheapest cruise we saw, with most up over $120. The Compass itself is a little run-down -- there's some rust and the furnishings are far from plush -- but it seemed perfectly seaworthy and the safety procedures solid. The staff were young and friendly and the passengers were mostly backpackers. Lunch was simple but perfectly decent. Perhaps the biggest drawback was the limited "natural history" support, but we were too busy watching the fish to have time to read or listen to information about them.
This cruise is definitely recommended, though when we go back we'll obviously try a different one so we can see a different part of the Great Barrier Reef.