Your Marketing Strategy must be clear, whatever it is.
Many businesses start out with very clear promises and prices, then eventually dilute their message by making changes in the service or product and forget to change their message.
An example of this in the retail world happened to me last weekend. I was staying at a hotle in LA. My first night there I was tired and had some work to do. I ordered room service, so I could get comfy and settle in to work.
I placed my order and it came as promised, but when I looked at the bill, there was a significant difference in to of the three items (much more expensive, of course).
I called down to ask about this and was told the prices had increased but they hadn't gotten around to changing the menus in the rooms. We're talking about a difference of $16.50 on this bill for one person.
I'm considering taking this up with corporate on principle. I make my livelihood delivering what I promise for the fee I will charge. They need to do the same.
Be sure that you deliever what you say you will for the amount you advertise or agree on.