I will be meeting up with my family in Houston and travelling with them. We have one night in Belize city, then are spending 8 days on Ambergris Cay at the Coral Bay Villas (
http://www.coralbaybelize.com/) My mom is great with this stuff and we like to travel over the holidays (previous destinations = Maui and St. Martin), so she organized it all. That being said, I don't really too much more, just that I am looking forward to it.
For the place I linked, the extra equipment was listed as: bathing suit and towel, mask and snorkel, fins and boots, and diving gloves. From another site I found these prices:
Masks range $ 60 - $ 90
Snorkels range $ 25 - $ 35
Fins range $ 60 - $ 120
* Dive booties range $ 35 - $ 45
* Gloves range $ 30 - $ 40
Other schools also made a dive watch and knife required, but thats not mentioned here.