When creating any design it is important to think about the psychology behind it. If you are creating a website, promotional flyer, or a logo then you need to think about the message you want to portray and the type of customers you want to attract.
Very often when someone views promotional material they go through a thought process. Firstly, what are they offering, secondly do I need it and thirdly how much does it cost? Once they have established this they can make a decision to decide if they want to buy it.
Some companies decide to not show prices and have a price on application button, or ask for a quote. For certain services or products this may be essential as they are bespoke and therefore need to be quoted on a project per project basis but for others where competitors are advertising prices, you may be losing out on sales.