Meal prep for busy people!

Christine
Hi! I'm a full time student athlete with a full time job and a part time job! I need to lose weight and while I am pretty active as an athlete and on my own, my diet is what's holding me back.
Do any of you meal prep? I have tried it in the past but the food doesn't always make it the full week. I have time to do it on Sunday's or even once a week. But I certainly don't have time to do it 2-3 times. What's the easiet foods to make and the bet way to make the food last the entire week?
I'm not a picky eater, I'm open to all types of food or even eating the same thing everyday. I just need something simple and not crazy expensive or time consuming.