As one of its daily deals, That Daily Deal offers this Battle Bots R2-D2 vs. Dalek T-Shirt in Silver for $9.99. Coupon code "FRIDAYBATTLE" drops it to $7.49. With free shipping, that's a buck under our expired mention from two days ago and the lowest total price we've seen. (It's also $10 under any Dalek-themed shirt we could find elsewhere.) It's available in sizes S to XL. Deal ends April 18.
Note that size XXL is also available for 99 cents more and 3XL for $1.99 more.