I’ve done some freelance web design and print design work. As I do more work, I’m getting more referrals which is good. Recently (today) I did work for a person in an office that has many coworkers who decided they want the same design (print). How do I go about charging more people for the same design? What I did today was not charge for the initial design and then just charge everyone in the office a flat fee which covers the cost of the initial design plus some. Was this the correct thing to do or should I charge each individual for the design (each person had slight changes to the design)?

Another question is how to go about the printing of the materials. Is it correct to help them and have them go through a printing company (online printing service) or should I charge an amount that covers the printing and design? This would “look” better because I would be in charge of the entire process however, I don’t want to be responsible for mishaps with the printing company. Give me your thoughts.
Thanks for your help,
rb18b