Operating cash flow is the lifeblood of a company and the most important barometer that investors have. Although many investors gravitate toward net income, operating cash flow is a better metric of a company's financial health for two main reasons. First, cash flow is harder to manipulate under GAAP than net income (although it can be done to a certain degree). Second, "cash is king" and a company that does not generate cash over the long term is on its deathbed.
(above from investopedia)
I really like BIOF Ops cash flow especially for a stock price under $1.