Motorcycle helmets MUST be worn together with suitable knee high boots. Junior riders (upto 16 years old) must wear long sleeved tops (the arms must be covered) as well as gloves which cover the hands and fingers. The ACU handbook has more details on this.
New adult bikes cost around £5k - £6k with used machines costing anything from a few hundred to a few thousand pounds. A good reliable competition bike can be purchased for a round £2K
Good bike set up and preparation is important so you may need to learn new skills with the spanners!
Many new riders buy bikes which are too powerful, this only deters confidence rather than build it.
Young riders need to refer to the ACU handbook to see which engine capacity they are allowed to ride.
Electric bikes are now being used by some youths and classes are being created for these. It's only a matter of time before we have adults on electric bikes....