Should I tip a ski instructor for a 2-hour group lesson if done well? If so, how much?

Ski instructors are poorly paid, and rely on tips to supplement their income, the same as servers. If you are satisfied with the lesson, 10 - 15% is appropriate. If you want a more "personalized" group lesson- try tipping before the lesson starts.

Yes. A typical tip is around 10-20% of the lesson price at the end of the day.

Most ski areas only pay instructors a small hourly wage. For example, base pay at Vail Reorts is $10 per hour. For a private lesson, the client pays $755 to Vail, and the instructor only gets paid $60 (which works out to around $45 after taxes.

A typical tip for a private lesson is around $100-$200 per day.

No, not for a group lesson. They get paid by the resort.

i would say no, not for a group. but if you feel like you should... maybe $15?