Grocery outlet (that I love) frequently sells a pound of frozen wild red yellowfin tuna in its freezer section for $6.99. The taste and quality are awesome. I buy it up. I rub at room temp with whatever seasoning blend I feel like; I usually concoct some type of Cajun/creole spice rub, and let sit for 15 minutes.
Heat up a non-stick skillet over medium high heat. I sear each side (no oil) 3-5 minutes depending on thickness being sure to never let the middle cook through.
8oz (measured from raw) tuna over a bed of 1 cup of rice with 2 tbsps low cal teriyaki sauce and 1 tsp sesame seeds. Runs around 500 calories, ends up being 2 "fancy meals" for about $4 cumulative cost. Also, my belly feels so spoiled. Tuna so tender you can cut it with a spoon.
I spent 8 minutes cooking tonight and 4 to clean up. You can do this.