I pay $55 AUD for an hour's lesson on a school horse. I think its $45 if you have your own. My lessons are western/hunter under saddle kinda stuff.
My 2 instructors are quite nice. I get to ride in their saddles, use their show saddles and gear at shows if I show their horses. My lessons are meant to go for one hour but they go for longer. I'll end up having an hour and a half riding lesson, then she'll get all the other girls to tack up, we'll have a group lesson, then a ground work lesson.
I'm part of my barn's show team, so I travel with them to shows and show their horses.
I also tend to get longer lessons because I work for riding time. EG, mucking out stalls, lunging horses, catching horses, being a trail leader.