On a monthly basis your attorney should send you an itemized statement of services rendered. Included in that statement will be any misc. expenses such as mailings, copies etc.. This statement should break down the costs based on hours or fractions thereof for each item and then apply them to his hourly rate.
I hope this helps. I would ask him or her to thoroughly explain to you the process and their rates etc. You deserve to know. Good luck. Let me know if I can be of any further help.