Directly from being a referee not much, it's only in the last 2-3 years that they became professional and got anything over and above general expenses.
believe before they became professional that match fees were approx �500 a game so it was a reasonable amount but obviously a fair bit of commitment required
in the last few years they are now earning about �1,000- �2,000 a game i have a friend of a friend who is in the know. They get expenses too, live a great life and are well known by professional footballers, what a life!! Plus most of them have continued with full time jobs but they do have to do courses every 3-4 weeks.