As one of its daily deals, THAT Daily Deal offers this Flux Capacitor T-Shirt
in Blue for $5.99
for shipping. That's tied with last month's mention and the lowest total price we could find for any similar T-shirt by $10. It's available in sizes S to XL. Deal ends October 29.
Note that size XXL is available for an extra 99 cents, and size 3XL for an additional $1.99.