Thinking of this from a different angle, and I'm just thinking 'out loud' but could you possibly have a poster that basically invites them in to grab a price list. I'm just thinking that way you get them in to the salon, get the chance to chat to them, get them to soak up the ambience of your salon and have some face time. I would be concerned that some would look at a price list in a window and carry on walking if they didn't like the price, obviously you don't want bargain hunters, but sometimes getting someone inside an establishment and being able to chat to someone makes that person realise that there is a blooming good reason why you charge what you do- ie polite staff, great work, relaxing salon atmosphere, quality products and that they are valued as a customer. Having prices in the windows would also worry me that if they look at the prices, then think I'll ring them later or pop in later, but if they physically have to come in and ask or grab a price list you get the opportunity to interact with them.
I'm a home salon so no window, I do display all my prices on my website but I also have an informative website which grabs my clients attention, it's laid out will, with text, videos, pictures that help my clients decide what treatment to have and also shows them I know what I'm doing lol. That's my virtual shop window.
xxx