As one of its daily deals, Hobo Ninja offers the I'm A (Netflix) Marathoner T-Shirt in White for $9.99 with free shipping. That's the lowest price we could find for a Netflix marathon-themed t-shirt elsewhere by $12. It's available in sizes S to XL. Deal ends October 30.
Of note, it's available in XXL for 99 cents more and 3XL for an extra $1.99.