Weigh insecurity

I never really share on here but I’m having a few weigh issues. I’m currently weighing in at 110 pounds give or take but last week I was 130 pounds. I don’t have a ton of stomach fat but it’s definitely noticeable. I want to start maintaining my weight and possibly gaining muscle but have no money for the gym or any special diets since I’m only a teen. Can you guys help me out maybe with certain foods or at home workouts. If you see this and help me your amazing and thank you.