When it comes to fitness, summer is truth-telling time. Gone are the sweaters and parkas that gently disguise winter Buddha bellies; in their stead come all-too-revealing miniskirts, swimsuits and sundresses. How to wrestle an untamed body into summer shape without breaking the bank? Start by evaluating your budget, schedule and (most important) commitment level, says Liz Neporent, wellness consultant for Goldman Sachs and coauthor of The Fat-Free Truth. "Exercise has tremendous health benefits," she says. "But immediately buying a $3,000 treadmill may not be the best plan." Here's how to find the most cost-effective workout for your lifestyle.

Personal trainer
Pros If you're having difficulty squeezing in workout time, a trainer will give you an appointment that you and your family will respect more than "But I was going to work out tonight." Trainers can help you achieve a specific goal or maintain your overall fitness. They can also tailor your routine to meet your abilities and interests.
Cons If your life is already overscheduled, adding another appointment might be more stress than it's worth. If you cancel suddenly, chances are you'll still have to pay—and trainers are expensive, costing $200 (or more) per hour. An alternative: Hire one for a few sessions to get started, then add a refresher course every six months.

Gym membership

Pros Gyms provide more variety than you'd get working out on your own, plus perks like saunas and steam rooms, fluffy white towels and a staff that assists and cleans up after you. The medley of weights, machines and Pilates and spinning classes is hard to rival. What's more, you can't help but feel pumped up by the atmosphere as well as the other people working out around you. Most people visit the gym at least 90 times a year, says the International Health, Racquet & Sportsclub Association; since the average membership costs $30 to $35 per month (plus initiation fee), the overall investment comes to less than $4 per visit.

Cons If you think writing a fat check to your gym will give you an incentive to work out, think again. "That's why gyms make so much money," says Susan Lewis, MD, director of women's programs for the Center for Sports Medicine at Saint Francis Memorial Hospital in San Francisco. "People pay in January, and a month later they've forgotten the pain of writing the check." Consider a month-to-month membership, which usually allows you to bail if you don't end up going. Choose a gym near your home or office—one with a schedule that matches your own.

Studio classes
Pros If you don't have the budget for a personal trainer or the discipline to work out on your own, signing up for a studio class is a great way to carve out exercise time. Classes can cost anywhere from $10 to $35 (often discounted in packages of five or more), and they're usually drop-in, so you don't have to pay for those that you miss. The per-class price doesn't include the perks you'd find at a gym, but the quality can be better, Neporent asserts: "Hard-core yoga and Pilates gurus often teach at studios." Studio classes can be smaller and are sometimes designed to meet each group's fitness level; some even boast superior equipment, such as Pilates or Gyrotonic machines. For many women, however, the intangible rewards—such as an increased sense of intimacy and calm—are the most important considerations.

Cons At a studio, there probably isn't a shower, so no time saved there. Plus, when you factor in driving time and having to adhere to someone else's schedule, this can easily end up consuming an entire evening. Chances are good that you won't find saunas or even locker rooms. What's more, the quality and atmosphere of each studio class are dictated by the teacher—maybe you'll love her, maybe you won't. Most studios offer a complimentary class, so the best way to find one you like is to shop around.

At-home exercise machines
Pros You're at home, so you set the schedule. Want to watch American Idol while riding an exercise bike or sneak in a few minutes on the treadmill before dinner? Go for it! Dr. Lewis is such a fan of the at-home workout, she refers to her StairMaster as an alarm clock—every weekday, she rolls out of bed at 5:00 a.m. and jumps on the machine. Basic gym equipment works well in a home setting: Treadmills are a great way to drop weight, while elliptical trainers offer a low-impact workout.

Cons You're at home, where distractions are ever present. Many people who buy a workout machine expect to get superior results by sticking to one type of routine, but without variety, the body can become resistant to change. And buying gym equipment is a major investment: A high-quality machine or home gym with lat pull-downs and leg and chest presses can cost more than $1,000. Consumers on limited budgets should look into renting for at least a month or two before purchasing: Unused machines often end up as very expensive clothes hangers.

Fitness DVDS
Pros If you have the space—that is, a room where you don't have to compete with your kids and husband for the TV—it's hard to beat the convenience of popping in a workout DVD and sweating it out in the comfort of your own home. The main appeal, of course, is that you can choose to crunch and condition at an hour that's convenient for you. Popular workouts such as More than Mat Pilates cost a mere $15 each, or for about the same price you can buy DVDs that come with the equipment you need for the routine (balance balls, resistance bands, and so on).

Cons A DVD isn't nearly as effective as a live class, warns Dr. Lewis. For one thing, DVDs are designed to suit the broadest possible audience, so their overall vibe is middle of the road: not too fast, not too slow. A made-for-TV workout is also a far more passive experience, so people have a harder time sticking with it. "I've never met a home-video exercise fanatic," Dr. Lewis admits. "It's great for a month, then it gets boring."

Walk/run with a friend
Pros For the price of a pair of running shoes, you can make every step count. Walking or jogging with a partner is a great way to stay fit, and definitely the least expensive. Not only will you be less likely to bail on a standing date, but it's probably the most fun way to exercise, since you get to socialize in the great outdoors. If the only running you do now is after your toddler, start slowly, walking 15- or 20-minute miles (wear a pedometer) and gradually increasing your speed and distance.

Cons Exercising with the wrong person can actually decrease your motivation—and the change could affect your friendship. "If you're waiting on the corner at six a.m. and your friend decided to sleep in, you won't be happy," says Neporent. You also need to find a safe, enjoyable place to run—not a major highway or the mall—and you must learn to summon the will to continue when cold or foul weather hits. "On snowy days, it can be really hard to get out there," Dr. Lewis explains. "And if you don't do it, you aren't saving on anything."