Cubavera offers its Cubavera Men's Essential Polo in 15 colors (CM Silvery Moon pictured), with prices starting at $7.99 (although most colors/sizes are $14). Plus, coupon code "CVAFSHIP" bags free shipping. That's a buck under our February mention and the second-lowest total price we've seen. (It's a current best by as much as $12, excluding the below mention.) It's available in sizes S to XXL, although not in all size/color combinations.
Of note, Amazon has it in 17 colors, with prices starting at $12.99 with free shipping for Prime members. (However, most colors/sizes are $15 or more.)