Hanes offers its Hanes Men's or Women's Christmas Sweatshirts in 18 styles (Women's Mini-Elf Graphic pictured) for $6.99 with free shipping. That's the lowest total price we could find by $6. They're available in sizes S to XXL.
Of note, they're also available in kids' sizes for $4.99 with free shipping. That's $5 off list and the lowest total price we could find.