Most people in a consulting business start out by underestimating what to charge and gradually revise upwards. You can try to figure out approximately how many hours it will take you to plan a trip for someone and then give them a quote based on what you’ve determined you would like to make per hour. (You don’t need to tell them your hourly estimated rate.) As you plan more of them, you will have a better sense of how much time it actually will take and also it will take you less time since you have done it more. You also don’t want to charge too much in the beginning because you have to build up a customer base.