Starter keyboards are usually the portable type offered by Yamaha or Casio that include built-in speakers. The better ones will include full size keys and touch sensitivity and those even further up the price scale may include MIDI or a USB connector.
Most starter/portable keyboards also include a headphone input that mutes the on-board speakers when the headphone jack is inserted so that practising can be done without disturbing. The price range of starter keyboards is generally between £60 and £250 however the important point to note is to choose one with full size keys so that the novice or beginner does not find the transition strange when playing a normal piano.
Some starter keyboards may come with instructional CDs or DVDs so that the beginner can better understand the theory of playing music. If this is not the case then there is plenty of independent instructional keyboard books and DVDs available to choose from.