How do I have my receptionist tell my clients that my haircutting prices are going up?

I would have him/her advise the customers when they walk in, nicely of course. I would also post a sign letting customers know of the increase :)

When my sister-in-law raised her prices she put up a sign approximately 6 weeks in advance of the raise. Her reason was that most customers were in there every 4 - 6 weeks so they would be aware of the increase well in advance.

So, remember in keeping the customer happy it is best to let them know way in advance.