Spending money on a gym membership, which can add up to $500 or more a year, is not an option for many budget-cutters this year. But you still want to stay in shape, right? Consider part-time work as a fitness instructor. I did it, and so can you. Here's how, in four steps:

1. Decide what kind of class you want to teach. I initially thought I'd teach yoga, but decided my skills weren’t advanced enough. That’s when some fitness Googling (Stock Quote: GOOG) led me to an outdoor fitness boot camp near my apartment in Austin, Texas. The cardio and strength training class met at a public park four times a week for three weeks, and felt a lot like the conditioning I did for high school sports. I signed up for an initial cost of $195, made friends with the instructor and quickly informed her of my desire to get into her line of work part-time.

It's fairly common to strike a deal with the gym or the instructor to work out for free while you learn more and pick up a class here and there. This was perfect for me, since it crossed that gym membership need off my list and gave GOFit a backup boot camp instructor if they needed one. This tends to be the way of falling into the field: You find a class, a gym or a type of workout that you really enjoy and go to it as often as possible. Make friends with the instructor, and offer to teach if he or she needs to miss a class. If teaching is your goal, call around to various gyms, and see if they have openings before you sign up.

2. Get yourself certified. State governments neither offer nor require a group fitness instructor certification to teach classes, but most employers do (and they won't be be willing to pay for your time if you're not certified). The two main certification boards the boot camp owner pointed me toward are the American Council on Exercise and the Aerobics and Fitness Association of America.

The exam and certification for AFAA was $299 and the study materials were $44. ACE recently dropped its exam fee to between $200 and $249 but they charge $380 for study materials. Certification is good for two years at either entity. I went for AFAA, which was not only cheaper, but included a full-day workshop, a practical portion of the exam and (unlike ACE) a written portion, too. For certification, I was required to know all of the major muscles, which exercises worked them most efficiently, how to do those exercises safely and how to organize and teach a class within a specific time frame.

The textbook and workshop more than prepared me for the exam and all that was left was my required proof of CPR certification and I was ready to teach. While they recommend studying for at least a month in advance, I condensed it into about two weeks and passed with no problems.

3. Know your risks. For the most part, it is up to your potential employer to have liability insurance and to provide waivers for your students to sign. All waivers include the very basic, yet necessary caveat, "Do not begin any fitness program without first consulting with your doctor." While the burden is on your employer, it is up to you to confirm they are covered by asking about their insurance and waivers, making sure you are protected. If you're not satisfied with their answer, insurance and certification agencies offer liability insurance for individual fitness instructors at an annual premium of between $200 and $300.

4. Set your rate and work up a sweat. I get paid anywhere from nothing (if not enough people show up for me to teach my own class) to $50 per hour, depending on how many sign up. This is the major drawback of the job. Like all non-essential service industries, the fitness business is facing a slump as people, like me, cut gym memberships from their budgets. But, for me, getting a free workout was enough of an incentive. The weeks I get paid are an added bonus, and the certification is something I can use no matter where I end up.

—For the best rates on CDs, mortgages, savings, credit cards and more, enter your ZIP code at BankingMyWay.com.