In this paper we present a low cost sub-optimum technique for the evaluation of the two-dimensional (Delay-Doppler) Cross-Correlation Function in passive radar. Its performance is characterized both in terms of computational load and expected signal-to-noise ratio (SNR) loss, compared to optimum efficient algorithms and alternative sub-optimum approaches. The comparison is conducted with reference to typical case studies representative of aerial or maritime surveillance applications. The proposed approach is shown to allow a better control of the SNR loss to be accepted that can be more flexibly traded with the computational burden. Therefore it can be regarded as an effective solution for real time operation in computationally intensive scenarios as those expected for passive radar based on digital video broadcast transmissions.