Pricing of services is tougher than pricing of goods. While the latter can be priced easily by taking into account the raw material costs, in the case of services there are attendant costs--such as labor and overhead costs--that also need to be factored in.
A restaurant not only has to charge for the cost of the food served but also has to calculate a price for the ambience provided.
Source: Boundless. “Product, Placement, Promotion, and Price.” Boundless Marketing. Boundless, 21 Jul. 2015. Retrieved 08 Sep. 2015 from https://www.boundless.com/marketing/textbooks/boundless-marketing-textbook/services-marketing-6/marketing-mixes-for-services-50/product-placement-promotion-and-price-251-3479/