it is different everywhere you go. one that I go to is $150 for 3 months and the other is $30 a month. how much you pay for your lessons shouldn't be based on what others pay it should be based on the following...
1.before you even start you should find out how well the other fighters have done under this person's training
and secondly whatever the price is can you afford it based on your level of income
there are some gyms that if you can't afford dues they will let you do something else for the gym to make up for the money. clean, paint, if you have any type of carpentry skills build something etc.