What is the cheapest and best way to eat healthy daily and build body mass, but not too much mass like a body builder.
Go live on an organic farm. Work for your room and board. Can't get cheaper than that. Eat lots to build mass. Eat as much as you can, and it will be healthy since it's an organic farm, eh? And cheap - because you don't have to buy the food.
Look up WWOOF ing. Seriously. You'll know which reference I'm talking about when you see.
We pick up wwoofers hitchhiking all the time.