No Extra Money For Equipment/Workout Tips

Hello! I'm 37 years old and I'm about 5'8" and 170 pounds. My ideal weight is around 150. I know I'm not going to be able to gain much without having any weights, nor do I have the extra money to spend on a bunch. I'd like to know if it's possible to at least get a nicer looking chest and a leaner frame by just doing body weight exercise and cardio + diet. What exercise programs would you recommend?