The Product Line Engineering approaches (PLE) to software development are promising in matter of quality, productivity and time-to-market. Some results achieved in industry can prove that. But managers need quantitative models reassuring them concerning the important initial investment they are going to commit. This paper reports on the need for such economic models for reuse as well as the underlying supported tools. Thus, we introduce a new Software Cost Estimation Model for Product Line Engineering that we denote as SoCoEMo-PLE. This model is based on two previous models: the integrated cost estimation model for reuse in general and Poulin?s model for PLE. In fact, we present a new model which takes into account PLE software development cycle approach and takes some features of the two previous cost estimation models. The tool supporting SoCoEMo-PLE is described and an UML modeling is presented. Results of a preliminary experiment in the use of the model and the tool are reported.