tighten one's (или the) purse strings (или purse-strings)

As money was so tight with him that he exulted in the opportunity to economise at her expense, he had tightened his purse strings to the limit and ground her further under the pressure of his heel. (A. J. Cronin, ‘Hatter's Castle’, book II, ch. 5) — И так как теперь Броуди был стеснен в средствах и радовался всякой возможности экономить на семье, то он все туже стягивал мошну, и миссис Броуди становилось все труднее и труднее.