A hexacopter is essentially a helicopter with six blades rather than two. The extra blades add stability to the body of the craft, making hexacopters ideal for carrying extra weight such as surveillance equipment. For this reason - model, radio-controlled hexacopters have become a popular and cost effective way to take aerial footage, and top end models are used by major news organisations like the BBC.
Think about how you plan to use your hexacopter before you buy one. For instance, if you are using it for surveillance, choose a model which has a longer flight time. If you plan to take aerial video or photographic shots, choose a model which can accommodate your camera, or has a built in recording device.
There are hexacopters to suit every budget, although even the basic models are not cheap. To save money, buy a DIY hexacopter kit, and build it yourself at home. However, if you do not have much experience of assembling rotorcrafts, it may be best to pay a bit extra and buy a ready-made hexacopter. If you are buying a second hand hexacopter, make sure you get a copy of the user manual so you can try to make any minor repairs or alterations yourself.
Some suppliers will offer training as part of the sale. If you do not have access to training, take your time getting used to your hexacopter. Practice taking off and landing before attempting long flights, and do not attach expensive equipment to your hexacopter until you are confident that you can use it correctly.