My daughter's lessons are $40/hr private, $35/1.5 hr semi private (2 people) and $30/ 1.5 hr group (3+ people). During the winter her lessons are semi private, usually riding with a teenage girl who has been helping at her lessons since she started 2 years ago (I'm talking missed 2 lessons of hers in 2 years. She adores my daughter).
The lesson starts with the kids getting their own horse (depending on the kid and horse, with appropriate supervision), the kids do a full groom on the horse. Tack up, then lead into the arena. After the lessons are finished, the kids also do a quick groom and return the horse to their stall/pasture.
The instructor tries hard to keep the kids on the same horse for their lessons. The kids and the horses form great bonds that way. (Okay, the same goes for adults, but I'm always there for kid's lessons.)
She is one of the more expensive western horsemanship/trail instructors around, but fortunately my daughter was gifted lessons for life from my uncle 2 years ago, so I haven't spent anything except to buy the helmet.