Cramer's Rule is a well known result giving the solutions of the matrix equation Ax=b for nonsingular matrices A. This rule is quite popular with students since it gives a concise concrete expression and a deterministic method for solving systems of equations. We consider the often overlooked "cost" of calculating solutions using Cramer's Rule. That the importance of the result is theoretical, not computational, is lost in introductory courses considering only small dimension linear systems.