How can I lose weight while being broke?

I am trying to lose weight. I'm 5'5" 155lbs. I went a period of my life when I hardly ate anything (I am a stress anorexic so when I stress I forget to eat) so now my metabolism SUCKS! I've been going to the gym and working out at least 30 minutes a day to try and help. I just recently got surgery on my heart so working out is kind of new to me because I was never allowed to do a lot of physical activity before so I'm learning how to do things, like run, without hurting myself. My issue is eating. I don't know how to cook and frankly I don't have time (Work 45-50 a week and full time at college) and on top of that I'm flat broke. I've been told to try meal plans like nutrisystem that way I don't have to cook but they are way too expensive plus I tried nutrisystem when they had a 50% off deal and I couldn't stand it (Tasted like powder). Does anyone have any suggestions to a premade or easy to cook meals (canned or not is fine)? I'm not eating enough calories now because I don't know how to cook and my doctor said thats the reason I'm still gaining weight. I love noodles so I eat a lot of spaghetti but I know thats not good for me, and I try to eat more salad but it goes bad sooo quickly. I've thought about just doing the walmart brand of lean cuisine (its only about $1.20 a box) and then ramen for dinner but if anyone has any suggestions that would be great. Thanks! I've already switched to just drinking sink water to save money and that has helped me lose about 5lbs but I've got 15 more I need to lose.