Off Topic-Tipping Dive Instructor (private lessions)

[Loves_Dogs]

Due to my work schedule I was unable to take the SSI dive classes at my local dive shop. They did offer private instruction, which I signed up for. My instructor has been great and I am down to my last 2 lessons. I realize with private instruction they do not make as much as when they teach a full class. I would like to tip him but do not know how much. I was thinking $100 or so. Any suggestions (esp if there are any instructors out there) would be greatly appreciated! Thank you in advance for the help.

[Middleager]

Perhaps if you provide a little more info it would help. $100 sounds a lot, but maybe you are getting some special lessons. What course/certification are you taking, is it the OW or more. Not sure if this is also including all the actual dives or just the classroom/pool instructions. What location, and what was the regular course cost vs private. And is he doing something extra-ordinary (e.g. keep adjusting schedules, give longer lessons/pool-time, lending you special equipment)? All those are factored.