Regal nails, Salon & Spa ( inside walmart)

I am complaining about the business prices.
I had my nails done and the price on the wall said $30.00 for a full set with powder.
I was charged $40.00. I did not even get a full set as I asked for powder on my own nails.
I asked why so much and the lady sent me to a guy to talk to. I told the guy that I was charged $40.00 for putting powder on my own nails no artificial nails and that the sign said $30.00.
Then my daughter was charged $25.00 for a full set with polish. They had a sign that they were promoting which was $5.00 off the $25.00. The sign again on the wall said $20.00 for full set with polish.