What are the running costs?

The cost of mains electricity to fully charge the battery is about 5p. Compared with the equivalent cost for petrol this equates to over 450km per litre of fuel or about 1,300 mpg!
Other than this there are no other significant running costs. You should carry out basic maintenance and servicing as you would with a normal pedal cycle; however the electronic components of the bikes are sealed units (motor, sensors etc) and therefore require no specialist servicing during their lifetime other than routine lubrication or cleaning as directed.