This paper presents a linear power sharing scheme for distributed generators (DGs) to save the overall total generation cost (TGC) in an autonomous micro-grid. The cost saving is realized by tuning the droop gradients of DGs based on their respective mean generation costs. Compared with the existing non-linear cost-based droop schemes, the proposed scheme uses linear droop curve and achieves better performance in TGC reduction. The proposed scheme has been tested experimentally for the micro-grid, first with all dispatchable droop controlled DGs and then with non-dispatchable DG included. Experimental results have demonstrated the good performance and effectiveness of the proposed scheme under different operating conditions.