Grandparents Tax Credit Act of 2017 This bill amends the Internal Revenue Code to allow a grandparent a refundable tax credit for up to $500 of the cost of household items (food, clothing, and other items typically used by or for the benefit of children) purchased for the benefit of a grandchild who is under the age of 18 if, for more than half of the year, the child lives with the grandparent and at least one parent whose adjusted gross income does not exceed 300% of the federal poverty level.