Yeah i put prices on some of my flyers, but i exclude conservatories, glass roofs, and velux's from that, and say call to get estimate..
Where i will arrange to meet with them, and see the extra bit that needs doing.
I only put prices on one that im comfortable doing at that price, NEVER to just "get" it, and drop a few months down the line.
usually, i say to a customer if you are friendly with your neighbours, have a word with them, to see if they want a window cleaner and if they have 2 or more cleans i'll give you a free clean for each one.. thats a great way to get extra custom.
BUT make sure your good to your word, and dont drop that neighbour in it, as they recommended you. You dont want them getting shirty with the other neighbours cos you screwed up somewhere.