nikon d3100

Although the D3100 has a built-in flash, you may want to control your lighting a bit more by having one or more flash units away from the camera. Even one flash positioned several feet to the right or left of the lens will give much better modelling than the camera's own flash. It doesn't really matter what flash you choose, so long as it can be triggered by the camera in some way. The traditional way of doing this is by a cable, which used to plug into a flash socket on older camera bodies but will probably now have an adaptor for the hot shoe. There are also units which can be triggered by the camera's own flash or by a wireless transmitter which attaches to the hot shoe. There are many websites which will give you a lot of information and hints and tips about using flash indoors and there are also whole books on the subject. Here are just two sites which a quick search found and which looked more helpful than most: http://www.lightstalking.com/indoor-photography http://www.expertphotography.com/take-better-indoor-photos-using-an-off-camera-flash I think that reading up about what you want to do and how best to achieve it will help you a great deal in deciding what equipment you need and may save you some expensive mistakes in the long run.