The Immortal Iron Fist. Vintage style design.
Where to buy online
TeePublic (US & UK)
Threadless (US)
Society6 (US)
Neatoshop (US)
You can find the design on t-shirts in most stores, but also on other products depending on the store (e.g. hoodies, mugs, stickers, notebooks, phone cases, greeting cards, cushions, socks etc).