I've run into the "Toothpaste for Dinner" webcomic a few times, but never ended up at this t-shirt shop until I was chasing down clip art and kept finding adorable cartoons linking back to the "Nataliedee" collection on SharingMachine.
I haven't ordered or inspected any of their products, but I love the wit and illustrations. This one isn't a current t-shirt - but it made me laugh. This one also cracks me up. I feel like this quite often, and the anthropomorphic smiley hammer getting all excited = AWESOMENESS.