My own bond (with PAS) may not be typical, but here are the details:
GBP6,000 for 1 year, reducing to GBP4,500 for the next 6 months and then GBP3,000 for the final 6 months - which my maths makes 2 years in all.
Items specified in the bond are the company induction training and the cost of the conversion course.
Now, if I were to hire a helicopter of equivalent size and capability to the MD902, I reckon I'd be looking at GBP1,000 per hour plus VAT. Given that my course was 8h 30m, followed by on-the-job training at the constabulary's expense, I believe that my bond was pretty reasonable.
Hope that helps