Walmart offers the Fruit of the Loom Men's Short-Sleeve Pocket T-Shirt in 13 colors (Black pictured) for $3.58. Choose in-store pickup where available to dodge the $4.97 shipping fee. That's tied with our July mention and the lowest price we could find now by $2. It comes in sizes S to XL.
Of note, it's also available in Big sizes in 11 colors and Tall sizes in eight colors for $4.58 with in-store pickup where available. It comes in sizes XXL to 4XL, or MT to 3XLT, but not in all size/color combinations.