if at all possible develope a relationship with a real butcher.
beyond that i try not to consider inferior meat so “cost effective” to me means buying in volume and doing some cutting and trimming myself.cryovac and freeze. the easiest way to go is to buy whole beef tenderloin. invest in a cryovac type sealer, maybe a scale and you’re set to go. you can do a tenderloin w/ a chef’s knife but a filet knife is sweet to have. the cash you save on meat will pay for the sealer in no time. plus you get to practice some knife skills and enjoy better quality beef along the way- for less money at the end of the day.