Tripod Legs: The Base of Your Shooting Platform
Tripod legs are usually made of either wood, carbon fiber, or, most commonly, metal. Aluminum legs are fairly lightweight, rigid, and durable. Carbon fiber legs are even lighter, but will be substantially more expensive and won't provide much added benefit to the average aspiring shutterbug. Expect to spend $100 or more on a set of legs that you can take everywhere you go for years to come.
Additional important features to look for are that the legs are independently adjustable so you can level your tripod on uneven ground, and that the minimum and maximum usable heights of the tripod will meet your shooting requirements. Make sure your tripod legs extend far enough that you can look through your camera's viewfinder when using the tripod, without having to bend over uncomfortably. Take note whether the tripod legs themselves extend to this height, or whether the center post must rise substantially from between the legs to reach this height. The higher the center post must extend, the less stable a shooting platform you will have.
Now check the minimum usable height of the legs. Look for a minimum height of less than 18 inches. A low minimum height will allow you to take clear shots from angles most people don't often see. However, you will probably use this feature infrequently, and let it influence your purchasing decision correspondingly.
The Tripod Head: The Control Center of Your Shooting Platform
Tripod heads are available with a lot of bells and whistles, and you can easily spend a lot more money than you need to, if you're not careful. The most important thing to keep in mind during your research is that you need a tripod head that will reliably lock in place, and not slip under the weight of your camera. Saving a few dollars through buying a weak tripod head erases the most important benefits of having a tripod. Fortunately, some of the most trusted manufacturers on the market have models available under $50.
Tripod heads generally come in two types: ball heads and pan-and-tilt heads. Ball heads allow you to quickly move your camera's position on all three axes, but making precise adjustments with a ball head can be tedious. Pan-and-tilt heads are more common. While moving your camera from one position to another can be a more manual process with a pan-and-tilt head, the ability to adjust each axis independently of one another makes precise adjustments easier.
Other important features to look for when shopping for a tripod head are a bubble level, and durable, usable adjustment controls. While the ground you're standing on may not always be flat, a bubble level ensures that your camera's shooting platform will be. Adjustment controls should be solidly built, so that you don't need to worry that a flimsy plastic knob will break off in your hand when you tighten it. Also, if you may be shooting in chilly environments, look for adjustment controls that you will be able to manage while wearing gloves.
Conclusion
Investing in a tripod kit can make your photography experiences greatly more rewarding, but it's easy to go awry when shopping and end up with a tripod kit that either doesn't live up to your expectations or makes you feel as though you alone put the salesperson's child through college. Most importantly, make sure that you are buying a tripod kit that meets your needs, not those of anyone else, now and in the future.
Be sure you invest in something that is stable enough to hold your camera and any heavy lenses you shoot with, and something that you can depend on in whatever environments you shoot. Hopefully now you feel confident that you are knowledgeable enough to make an informed decision at your camera store, for the right tripod kit will be an essential and reliable part of your photography toolbox for years to come.