You have to charge what you are worth! Figuire your overhead out, how many workable hours you have a week then you'll have an idea. Example: If you OH is $1500 a month and you average 30 workable hours per week you need to charge $12.50 per hour just cover you OH. Add materials, time on the job, install etc...
I would charge $100. per banner, one sided, $150. two sided. Installs $75 per hour one guy, $130.per hr two guys. Extra for bucket truck. Good Luck