A gym membership isn't for everyone. If you prefer working out at home, or if you only work out indoors in the winter, then a home gym is much more your style. Whether you have a whole room dedicated to fitness or you just have a small corner, you can get in shape without leaving your house. Think about your fitness goals and then look for the pieces that will help you reach them.
Choose a place in your home that you'll really use. This may mean finding a spot in a room with a television, so you can watch a show while you work out. Or it may mean using a room right next to your bedroom, so you don't have to walk too far when you wake up for an early morning routine. Make sure there aren't too many distractions; if you can see your email inbox filling up on your computer monitor, you may be tempted to cut your workout short, and that won't help you reach your goals.
Think about the ways you like to work out. You probably already have an idea of the exercises you like to do as well as the things you don't like as much. This should make it easy to narrow down your choice of machines and other equipment. For example, if you don't like running outside, you probably won't like running on a treadmill, so you may want to consider and elliptical or an exercise bike. But if running is your passion and you just need a place to do it when there's snow on the ground, then a treadmill would be perfect for you.
Consider the space you have. Home gym machines are sometimes rather large, so this is important. Before you buy a treadmill, think about the place you're going to put it. Is the ceiling high enough that you can stand up on the platform and not hit your head? This may be an issue if you're setting up your home gym in your basement. Do you have enough floor space for the machine you like? You may need to shop for a smaller option, if not.
Balance strength training and cardio. Home gym machines are perfect for getting a good cardio workout, but you'll probably need separate weights to get strength training in. A small set of dumbbells may be enough, or you may want to try using a kettle bell. (If you haven't used them before, pick up a DVD or a book on how to get the most out of them and not hurt yourself.) If building muscle is one of your main goals, you may want to look into a weight bench and some barbells.
Make sure you have all the basics. If your machine or weight bench needs floor mats to stay in place, be sure you have those. A storage stand for free weights may also be necessary. And of course, don't forget to buy a good pair of athletic shoes and some activewear.