stick to your prices, if some one else is cheaper, thats there problem, they will soon give up when they work all week for nothing, i would just flyer there area every two months sp people know there is other wc around, when i started i underspriced a few jobs my self and to be honest cant be bothered doing them as they arnt worth the money,
now i charge a £1 a window, if people dont like it thats up to them, there is no point being a busy fool