this is how i price my work at the moment soon it will be higher as i wont be needing as much work
top windows on a normal house i price them at £1.50 each, this could consist of three panes of glass and a small opener, or 2panes of glass, basically if its not a bay window and no bigger than three panes £1.50, if it is bigger i double it, do count the windows round the house and then times them by !.50 or for every 2 windows £3, etc etc
down stairs i go on £1 per window and window here is dominated by even thee smallest piece of glass, i.e a front door with glass in it is £1, a window beside it, normal size or 10cm by 10cm that's also £1, for the fronts of an average i am for £5-7
for conservatories i don't really have a price scale, i look at it, and work out how long it will take me, i.e 20mins and then half it, 20mins = £10
also if you are currently employed, don't give up your job yet, go out canvassing leaflet dropping advertising etc, and get yourself a days works, and take a day off work to do it in, or maybe a Saturday, only quit your job at absolutely the last point,
i know in Oxford you can earn in excess of £200 maybe some days a bit less or other days more, if in your current job your earning £1200 after tax you need six full days work every month or 9 full days every size weeks, depends on how often you want to clean the windows, ( i find i can get higher prices if i clean houses every 6 weeks) you can do 4 days worth of work in 4 Saturdays, that's 70% of your work done and you only need to find another 2 days from somewhere.
Hope you can understand it and hope it helps