You can buy a new wireless keyboard with trackpad for around £30, you can of course pay more. A specialist keyboard such as those used in the medical profession can cost you upwards of £300 as they are designed to be used in specialist environments.
Of course most people will just want a standard run of the mill wireless keyboard with either a trackball or a touchpad also known as a trackpad. There are two option available as some people prefer the pad to control the mouse whilst others find it easier to use the ball to control the mouse. Depending on your preference and your requirements you may want a mini keyboard or a larger full size keyboard. If you are after something to use infrequently, maybe to control a multimedia centre, you may prefer a small keyboard that you can stow away easily and won't take up much room. If however you want a wireless keyboard to replace your current computer keyboard then you may prefer a full size one.
Most keyboards will be powered by standard batteries, however these need to be replaced when they run low. You can however get a wireless keyboard with a charging base or dock. These have built in Li-ion batteries that are charged when they are on the base which means the keyboard is always ready to use.
One such keyboard is the Logitech diNovoEdge which comes with its own charging base which means no need to replace batteries. The diNovoEdge has a sleek black gloss design and is quite slim. The touchpad features a touchdisc that enable fast scrolling and the built in lithium ion batteries means that you never have to worry about having a spare set of batteries in the house or office.