I'm a huge fan of band tees. Obviously it's preferable to buy them from the artist (or from somewhere where the artist is getting some revenue) but this isn't always applicable- some artists are simply too old or obscure or maybe they just have shitty band tees.
I decided to use a screenprinting service to make my own Muddy Waters tee, I based the image on his "After the Rain" album cover (he's naked, covered in water and holding a frog. I think it's the coolest.)
Pretty good results. I used "Spreadshirt", and chose the American Apparel blanks. Cost about $30-$35 total. Shirts are super soft with a pretty nice fit as long as you size up. They're also tubular knit which is great.