Camera Types
If your camera is a small point-and-shoot, any light one-piece tripod will do. You can buy these in any department store for less than $50. If your camera is a more sophisticated digital single-lens reflex, consider a tripod base that is separate from the head. These are generally sturdier, and the heads provide more precise control.
Tripod Material
Most tripods for consumers are made of aluminum or carbon fiber. Aluminum is less expensive, but is more prone to transmitting vibration, and is heavier than carbon fiber for the same level of stability. As of mid-2011, for about $130 you can buy a good aluminum tripod that supports 8-10 pounds. A heavier, sturdier unit that supports up to 15 pounds costs about $160. Carbon fiber versions of the same tripods cost about twice as much.
Tripod Heads
There are two main types of heads for still cameras: pan-tilt and ball head. The pan-tilt has knobs and levers that are tightened and loosened to precisely aim the camera. The ball head generally has one knob or lever, which is loosened to move the camera in any direction you choose. The pan-tilt is a little easier to set precisely, but it is slower to adjust than the ball head.
Dozens of manufacturers make a variety of heads. Expect to pay between $90 and $150 for a decent one. You should consider a head with a quick-release plate that attaches to the camera and allows for quick insertion and removal. The fittings are universal, so you can mix and match brands.
The Right Tripod
The right tripod is the one you will use. It should be sturdy enough to support the weight of your heaviest camera and lens combination, and light enough so that you will be willing to carry it to wherever you will be shooting. It should have the height and tilt adjustments you need. A good tripod will last many years. A poor choice will be replaced in a short time, so buy the best tripod you can afford the first time.