This paper presents a systematic review of all the solutions addressing different economic aspect of software product lines (SPL), e.g. SPL adoption cost-benefits, PL architecture decisions, SPL test strategies project cost overrun and so on, presented for the years 2000 to 2007. The goal of the review is to analyze the level of empirical application and/or validation of the proposed solutions with the purpose of mapping maturity as well as to what extent proposed solutions might be proven in terms of usability and usefulness. The important finding of this review is that although many economic solutions for SPL have been proposed over the years, the absence of qualitative and quantitative results from empirical application and/or validation makes it difficult to evaluate the potential of proposed solutions with respect to their usability and/or usefulness in relation to industry adoption. Suggestions have been presented to improve the existing situation.