As one of its daily deals, THAT Daily Deal offers this Officially-Licensed Star Wars Darth Vader T-Shirt in Black for $4.99 with free shipping. That's the lowest total price we could find for a similar Darth Vader T-shirt by $5. It's available in L and XL. Deal ends June 17.
There's a less expensive way, and then there's the way that works for you. The two may not be the same.