I have merch that no one buys, which doesn't matter much because I mainly made it for myself.
The one I bouhgt isn't really my character, because I don't like graphic shirts with characters on it that much. It's a fake logo I designed for my character's favorite brand. My main character always wears everything from that brand, it's kinda iconic so I wanted it for myself too 
Also a Redbubble user. I'm very pleased with their quality.