Ouch!
Thats only 50p a window!
Been a while since I was that cheap, you will make on the deal because you are WFP, but that is still rather low.
Rather depends on how you count up your windows too, i.e. do you break up even the large ones into standard size windows, or do you simple count up each window?
A price of my own would have been at least £50, utterly regardless of the location too.