Michael's right - photography only seems expensive until you really look into what it costs to do it as a business. Taking your cost and marking it up might get you by if you're doing side jobs and just want a little extra cash, but it's no way to run a business.

Getting a job as an assistant is a good way to show you how the shoot works but you might not learn much about the business end of things. You'd want to know what the photographer was paid to do the shot you assisted on, and how they got to that number. Thing is, people aren't usually big on sharing that kind of information - unless maybe you have a very good working relationship with the photographer, and that will take time.

There are some classes about how to do this - if you're interested in the PPA route (generally wedding and portrait photographers), they run a school in Texas in April that will answer a lot of these questions.