Offering a small group training can be as rewarding as personal training (1-on-1). I like the small group training as much as the 1-on-1 because I can train more people at once and make more per hour. Training up to 4 clients at a time is not that much more challenging from training one person at a time (at least for me). Yes it might require some extra work but the rewards are far better than 1-on-1 (mostly financial and time wise). I always like to challenge myself and training more than one client at a time makes me think more efficiently and makes it fun as well. As far as fee structure, I usually charge about 20% less per hour/person when I do groups up to 4 people.