When you can't afford food you can go to food banks.
If you're low income and are struggling to buy food look in your area for food banks and even consider applying for food stamps.
Also ask a church or if you go to church ask your church about assistance with buying food.
Most places have food banks and some churches may help with food assistance as well.
Also look around for soup kitchens who can also provide you with a free meal.
If things are so rough for you that you can't afford food, I highly recommend you take advantage of any government programs you can.
This can include the Supplemental Nutrition Assistance Program (also known as food stamps), WIC and cash programs.
If your child is 5 years old or under you may qualify for WIC which is Women's Infant Children Program that provides some payment for some food for your child.
You can't buy diapers with WIC but you can buy food for your child.