A number of shear wave speed estimators have been developed for crawling wave sonoelastography. In this study, a new low-cost estimator based on spatial wavelength averaging along the slow-time domain is presented while assessing its performance through gelatin-based inclusion and homogeneous phantoms. Results showed favorable estimation mean accuracy (93.8%) on the homogeneous phantoms at different concentrations. However, underestimation is present in stiffer inclusions with size smaller than the true wavelength of the interference pattern (83.4% mean accuracy). Still, the new approach's differentiation of stiffness allows rapid visualization of a tissue as a qualitative imaging technique. Moreover, the estimator results are suitable for further processing as a reference mask implemented in several shear wave speed estimators.