Then RYANAIR will pay you a princely Euro 130 odd per block hour for your Captainly services, with 5 on 5 off roster and it comes highly recommended by those on it. Other than that I believe contract rates DO obviously vary but it wouldn't be unreasonable to find yourself earning in the order of GBP 5500 odd per month on something provided by an agency (paid offshore). Have heard rumour of something on offer in asia at around 7k per month too (GBP).
Hope this is of some help.....