What is the best way to gain weight quickly, safely abd inexpensively? also, what foods should i eat?

Diet and muscle mass: To gain weight you have to consume more calories than you are burning. Do this in a healthy way though. Don't choose junk or fast food. Keep a well balanced diet and make sure you are getting all the nutrients you need. Don't cut out exercise as it is very good for you. Weight lifting and other muscle building exercises can help you increase your body mass.

Why?: Why do you want to gain weigh? Even if you are underweight, increasing your weight rapidly is not a good idea. Eat a well balance diet rich in fresh vegetables, fruits, whole grains, and low in saturated fats. You may wish to add fish and chicken in moderation.