On average how much do karate/kickboxing lessons cost a month?

I do think that's too much. My old Kickboxing (Freestyle Karate) club cost �35 a month for the same amount of training. It depends if it's a reputable club or not. Some clubs will charge more if their very well known or they have students that take part on televised events. Since that Kickboxing club I recently joined a Taekwondo club which is said to be one of the best clubs in Yorkshire and it costs me �45 a month for 3, 1 hour and a half lessons a week and I can train on open mat sessions as much as I want everyday for free. The benefit to this club is that it's a full time Dojo (Dojang to me) compared to a scabby sports hall at school that we train at in KB. If the club has good facilities you do tend to have to pay more. Up to you though. Give the club a try and you'll know after the first lesson if it's worth it or not.