I ride a brand new Aprilia rs 125 2007 which cost £3,715 brand new.
Full powered model 33 bhp, 120mph top speed, 0-60 5 seconds. At the age of 17 you can ride this if you pass your A2 license. Once this is done you can ride ANY CC size engine aslong as its restricted to 33 bhp. Once the two year period is over, you can then ride ANY size cc bike. If your 21 and other you can jump on to any CC bike/BHP. Although the test for motorcycle is becoming harder next year (alot harder) and being changed from 21-25.
It's great fun, alot better than the car. Although i've just currently done a deal on buying a GSXR 600 k6 2006 model, 130 bhp in back wheel, 160 no probs top speed. Obviously cant ride on road, for track only, but i cant wait ^_^ (stops going on)
CBT
Theory
Learning (5 day course £450 AGE A2 license under 21, DAS 21+)
Practical Test ( £60)