Shortly after Sam's arrival (which just about lined up with the wizard!rain of clothing), he took up an extremely casual 20th-century look: jeans, trainers and a hoodie, topped with an over-sized leather jacket. He also stopped shaving for a while:
He stayed more or less like that until the battle for Jhelbor, though he got rid of the jacket in Jericho.
After the battle, Sam's clothes were stained with blood, and he traded them in as quickly as possible for something that doesn't make him stand out so much in Rowan. He's got a semi-medieval look happening... tunic, trousers, leather boots and a long coat. His hair has gotten a little bit shaggier, though he now shaves his face regularly:
There's also a cloak that he wears over all that to help guard against the cold, but I left it out of the drawing for the sake of showing more detail. Also, y'all know what a cloak looks like anyway =P