Regarding consulting cost and value based model, i would like to mention Martin Fowler article regarding Utility vs Strategic projects (http://martinfowler.com/bliki/UtilityVsStrategicDichotomy.ht...). In a really clever manner Martin Fowler distinguish projects depending on whether the business function is a differentiator or not. "This is not a separation of IT by the nature of the technology, but into what technology does for the host business". This point of view should be taken into consideration whenever a consultant/freelancer/contractor have to prepare a quote for a project as the value of the project to the business can influence the cost.