It depends on where. If you are in a resort area, then the demand (and pay) for party/event planners is greater. If it is a more rural area, then, unless you get in good with the Chamber of Commerce or some specialty group that always uses your services for their events, then you might not be in much demand. The Internet has given people a door to many resources for party planning ideas, but there will always be people who want to hire someone to do the job for them.
I'm thinking of being a party planner when I am older, so I'm wondering if they make lots of money and about how much of it?