You only need part of rental gear. Each option is $10 per day per person. 
A. Regulator set --add $10
B. BCD -- add $10
C. Snorkel Set ( Mask, fins, boots) -- add $10 
D. Wetsuit--add $10
E. Dive Computer (required for Boat Dives) --add $10 
If you need A+B = $20 and so on.....
If 2 people need A+B for one day :  2X $20=$40
If 2 people need C+D for 2 days: 2x $20x2=$80
and so on.... simple math :) 
If you need prescription mask, please so mention it when you make booking, so that we can prepare it.