Cash flow models, like the free cash flow models, are used to value companies by looking at the cash they generate. These models discount the cash flows at an expected rate of return instead of just focusing on dividends. Free cash flows are the money a company makes from its operations after subtracting what it spends on things like equipment. There are two types of free cash flow models: one that considers payments to debt holders and one that doesn't. These models are considered reliable for valuing stocks. The article discusses the free cash flow to equity model, the free cash flow to firm model, and the adjusted present value model, which is a more advanced version of the free cash flow to firm model.